The costs and consequences of adequately managed chronic non-cancer pain and chronic neuropathic pain

Potential analgesic effect of a novel cannabidiol nanocrystals powder for the treatment of neuropathic pain

BACKGROUND

The current analgesics often prevent patients from getting effective treatment due to their adverse effects. Cannabidiol (CBD) is well tolerated, has few side effects and has been extensively investigated in analgesia. However, its oral bioavailability is extremely low. In order to solve this problem, we developed the cannabidiol nanocrystals (CBD-NC) in the earlier stage.

METHODS

In this study, we evaluated the nociceptive behaviours associated with neuropathic pain (NP) induced by the spared nerve injury (SNI) model. Assessment of pain threshold was evaluated by paw withdraw threshold (PWT) and paw withdrawal latency (PWL). The improving effect on the motor dysfunction was determined by rota-rod testing. To assess the neuroprotective effect, nerve demyelination and expression of peripheral myelin protein PMP22 were measured with myelin sheath staining and western blotting. Protein expressions in microglia of spinal cord were tested by western blot to explore the underlying mechanism.

RESULTS

Compared with the CBD oil solution, CBD-NC significantly reduced mechanical allodynia and thermal hyperalgesia in rats. CBD-NC could improve motor dysfunction induced by SNI in rats, significantly reverse the demyelination and increase the expression of the marker protein of peripheral myelin. Underlying spinal analgesic mechanism of microglia and related factors were preliminarily confirmed.

CONCLUSIONS

CBD-NC administration is an effective treatment for NP associated with SNI, and the analgesic effect of CBD-NC was significantly better than that of CBD oil sol. By contrast, CBD-NC has a fast-acting and long-term effect in the treatment of NP. Our study further supports the potential therapeutic effect of CBD-NC on NP.

SIGNIFICANCE

The absolute bioavailability of the CBD-NC intramuscular injection formulation can reach 203.31%, which can solve the problem of low oral bioavailability. This research evaluated the therapeutic effect of CBD-NC on NP associated with the SNI model for the first time. All available date showed that whatever the analgesic or neuroprotective effect of CBD-NC, it was significantly better than that of CBD oil sol., which was consistent with the results of the pharmacokinetic. This research supports the initiation of more trials testing the efficacy of CBD-NC for treating NP.

Barriers and facilitators for physical activity in people living with chronic pain: a systematic review and combined analysis

ABSTRACT

Chronic pain is a prevalent and complex health issue associated with physical, emotional, and social consequences. Management of pain is multifactorial and challenging; however, physical activity (PA) has consistently been shown to be beneficial. Despite this, PA levels among people with chronic pain are low. This study aimed to identify facilitators and barriers to PA among adults with chronic pain and analyse these using the structure of a validated behaviour change model: the capability, opportunity, and motivation behaviour change model (COM-B). We performed a systematic review of 6 databases and subsequent combined analysis including peer-reviewed primary research published in English up to November 15, 2023. Search terms consisted of 3 components: pain, PA, and facilitators/barriers. Quality appraisal of studies was conducted using appropriate tools. The systematic search yielded 40 eligible studies with a total of 2164 participants. The studies represented various chronic pain conditions, locations, and study designs. The key barriers to engagement in PA were the impact of pain severity, comorbidities, lack of knowledge about PA benefits, and time constraints. Key facilitators were a personalised approach, social support, and awareness of the benefits. The findings were categorised according to the COM-B model, allowing for the identification of modifiable factors. Person-centred approaches, education, and accessible environments were identified as important aspects to consider for successful PA promotion among people with chronic pain. Utilising the factors identified in the COM-B model is crucial for successful future interventions to increasing PA uptake and adherence in this population.

Gender differences in PTSD severity and pain outcomes: Baseline results from the LAMP trial

BACKGROUND

Post-traumatic stress disorder (PTSD) and chronic pain are highly prevalent comorbid conditions. Veterans dually burdened by PTSD and chronic pain experience more severe outcomes compared to either disorder alone. Few studies have enrolled enough women Veterans to test gender differences in pain outcomes [catastrophizing, intensity, interference] by the severity of PTSD symptoms.

AIM

Examine gender differences in the association between PTSD symptoms and pain outcomes among Veterans enrolled in a chronic pain clinical trial.

METHODS

Participants were 421 men and 386 women Veterans with chronic pain who provided complete data on PTSD symptoms and pain outcomes. We used hierarchical linear regression models to examine gender differences in pain outcomes by PTSD symptoms.

RESULTS

Adjusted multivariable models indicated that PTSD symptoms were associated with higher levels of pain catastrophizing (0.57, 95% CI [0.51, 0.63]), pain intensity (0.30, 95% CI [0.24, 0.37]), and pain interference (0.46, 95% CI [0.39, 0.52]). No evidence suggesting gender differences in this association were found in either the crude or adjusted models (all interaction p-values<0.05).

CONCLUSION

These findings may reflect the underlying mutual maintenance of these conditions whereby the sensation of pain could trigger PTSD symptoms, particularly if the trauma and pain are associated with the same event. Clinical implications and opportunities testing relevant treatments that may benefit both chronic pain and PTSD are discussed.

Identifying patterns of pain, depression, anxiety, interpersonal trauma exposure, and nonmedical prescription opioid use: Latent class analysis among patients with chronic pain

BACKGROUND

Chronic pain in the context of certain factors may be associated with potential for nonmedical prescription opioid use; however, identifying this risk can be challenging and complex. Several variables alone have been associated with non-prescribed opioid use, including depression, anxiety, pain interference, and trauma exposure. Prior research has often failed to integrate these assessments together, which is important as these factors may cluster together in important and complex ways. The current study aimed to identify classes of patients with chronic pain who have differential risk for use of nonmedical prescription opioid use, depression and anxiety, and pain severity, interference, and catastrophizing, and interpersonal violence exposure.

METHODS

Self-report and medical record data from patients (N = 211; Mage = 48, 69.0% women, 69.0% white) at a pain management center were collected.

RESULTS

Latent class analysis revealed 3 classes with (1) low probability of clinically significant depression, anxiety, pain, and nonmedical prescription opioid use (44.7%), (2) high probability of clinically significant depression, anxiety, pain, pain catastrophizing, trauma, and nonmedical prescription opioid use (41.3%), and (3) high probability of severe pain and nonmedical prescription opioid use (14.0%).

CONCLUSIONS

High-risk classes had either high levels of depression and anxiety, pain catastrophizing, and interpersonal violence exposure, or pain severity and interference. Future research should continue to explore these classes in large, diverse samples, and prospective study designs. Finally, results underscore that opioid use is complex, not easily identified by a single factor, and may be motivated by complex unmet clinical needs.

Cannabidiol (CBD) Products for Pain: Ineffective, Expensive, and With Potential Harms

Cannabidiol (CBD) attracts considerable attention for promoting good health and treating various conditions, predominantly pain, often in breach of advertising rules. Examination of available CBD products in North America and Europe demonstrates that CBD content can vary from none to much more than advertised and that potentially harmful other chemicals are often included. Serious harm is associated with chemicals found in CBD products and reported in children, adults, and the elderly. A 2021 International Association for the Study of Pain task force examined the evidence for cannabinoids and pain but found no trials of CBD. Sixteen CBD randomized trials using pharmaceutical-supplied CBD or making preparations from such a source and with pain as an outcome have been published subsequently. The trials were conducted in 12 different pain states, using 3 oral, topical, and buccal/sublingual administration, with CBD doses between 6 and 1,600 mg, and durations of treatment between a single dose and 12 weeks. Fifteen of the 16 showed no benefit of CBD over placebo. Small clinical trials using verified CBD suggest the drug to be largely benign; while large-scale evidence of safety is lacking, there is growing evidence linking CBD to increased rates of serious adverse events and hepatotoxicity. In January 2023, the Food and Drug Administration (FDA) announced that a new regulatory pathway for CBD was needed. Consumers and health care providers should rely on evidence-based sources of information on CBD, not just advertisements. Current evidence is that CBD for pain is expensive, ineffective, and possibly harmful. PERSPECTIVE: There is no good reason for thinking that CBD relieves pain, but there are good reasons for doubting the contents of CBD products in terms of CBD content and purity.

Pain relief and associated factors: a cross-sectional observational web-based study in a Quebec cohort of persons living with chronic pain

Objectives

Randomized clinical trials are used to evaluate the efficacy of various pain treatments individually, while a limited number of observational studies have portrayed the overall relief experienced by persons living with chronic pain. This study aimed to describe pain relief in real-world clinical settings and to identify associated factors.

Methods

This exploratory web-based cross-sectional study used data from 1,419 persons recruited in the community. Overall pain relief brought by treatments used by participants was assessed using a 0%-100% scale (10-unit increments).

Results

A total of 18.2% of participants reported minimal pain relief (0%-20%), 60.0% moderate to substantial pain relief (30%-60%), and 21.8% extensive pain relief (70%-100%). Multivariable multinomial regression analysis revealed factors significantly associated with greater pain relief, including reporting a stressful event as circumstances surrounding the onset of pain, living with pain for ≥10 years, milder pain intensity, less catastrophic thinking, use of prescribed pain medications, use of nonpharmacological pain treatments, access to a trusted healthcare professional, higher general health scores, and polypharmacy. Factors associated with lower pain relief included surgery as circumstances surrounding pain onset, use of over-the-counter pain medications, and severe psychological distress.

Discussion

In this community sample of persons living with chronic pain, 8 out of 10 persons reported experiencing at least moderate relief with their treatment. The analysis has enabled us to explore potential modifiable factors as opportunities for improving the well-being of persons living with chronic pain.

Adults with excess weight or obesity, but not with overweight, report greater pain intensities than individuals with normal weight: a systematic review and meta-analysis

Context

Over 1.9 billion adult people have overweight or obesity. Considered as a chronic disease itself, obesity is associated with several comorbidities. Chronic pain affects approximately 60 million people and its connection with obesity has been displayed in several studies. However, controversial results showing both lower and higher pain thresholds in subjects with obesity compared to individuals with normal weight and the different parameters used to define such association (e.g., pain severity, frequency or duration) make it hard to draw straight forward conclusions in the matter. The objective of this article is to examine the relationship between overweight and obesity (classified with BMI as recommended by WHO) and self-perceived pain intensity in adults.

Methods

A literature search was conducted following PRISMA guidelines using the databases CINAHL, Cochrane Library, EMBASE, PEDro, PubMed, Scopus and Web of Science to identify original studies that provide BMI values and their associated pain intensity assessed by self-report scales. Self-report pain scores were normalized and pooled within meta-analyses. The Cochrane's Q test and I2 index were used to clarify the amount of heterogeneity; meta-regression was performed to explore the relationship between each outcome and the risk of bias.

Results

Of 2194 studies, 31 eligible studies were identified and appraised, 22 of which provided data for a quantitative analysis. The results herein suggested that adults with excess weight (BMI ≥ 25.0) or obesity (BMI ≥ 30.0) but not with overweight (pre-obesity) alone (BMI 25.0-29.9), are more likely to report greater intensities of pain than individuals of normal weight (BMI 18.5-24.9). Subgroup analyses regarding the pathology of the patients showed no statistically significant differences between groups. Also, influence of age in the effect size, evaluated by meta-regression, was only observed in one of the four analyses. Furthermore, the robustness of the findings was supported by two different sensitivity analyses.

Conclusion

Subjects with obesity and excess weight, but not overweight, reported greater pain intensities than individuals with normal weight. This finding encourages treatment of obesity as a component of pain management. More research is required to better understand the mechanisms of these differences and the clinical utility of the findings.

Systematic Review Registration

https://doi.org/10.17605/OSF.IO/RF2G3, identifier OSF.IO/RF2G3.

Changing society, changing research: integrating gender to better understand physical and psychological treatments use in chronic pain management

ABSTRACT

Treatment of chronic pain should be multimodal and include pharmacological, physical, and psychological treatments. However, because various barriers to physical and psychological treatments (PPTs) exist, a better understanding of biopsychosocial factors leading to their use is relevant. This study aimed to explore the association between gender identity, gender-stereotyped personality traits, and the use of PPTs in chronic pain management. The ChrOnic Pain trEatment cohort, a self-reported data infrastructure resulting from a web-based recruitment of 1935 people living with chronic pain (Quebec, Canada) was analyzed. Gender identity was operationalized as women, men, and nonbinary. Gender-stereotyped personality traits were measured using the Bem Sex-Role Inventory (feminine, masculine, androgynous, undifferentiated). A checklist of 31 types of PPTs that can be used for chronic pain management was presented to participants (yes/no). From the 1433 participants, 85.5% reported using at least one PPT. Hot-cold therapies (43.4%), exercise (41.9%), and meditation (35.2%) were the most frequently used PPTs, but most popular PPTs were not the same among women and men. Women reported a significantly higher use of PPTs in general (87.2% vs 77.2%; P < 0.001). Multivariable and interaction analyses showed that identifying as a man decreased the odds of reporting the use of PPTs (odds ratio: 0.32, 95% confidence interval: 0.11-0.92) but only among participants who scored high on both masculine and feminine personality traits (those classified as androgynous). The high prevalence of PPTs use found in our study is positive. Our results are relevant for a more personalized promotion of PPTs for chronic pain management.

Where we live matters: a comparison of chronic pain treatment between remote and non-remote regions of Quebec, Canada

Objective

Where a person lives is a recognized socioeconomic determinant of health and influences healthcare access. This study aimed to compare the pain treatment profile of persons with chronic pain (CP) living in remote regions to those living in non-remote regions (near or in major urban centers).

Methods

A cross-sectional study was performed among persons living with CP across Quebec. In a web-based questionnaire, participants were asked to report in which of the 17 administrative regions they were living (six considered "remote"). Pain treatment profile was drawn up using seven variables: use of prescribed pain medications, over-the-counter pain medications, non-pharmacological pain treatments, multimodal approach, access to a trusted healthcare professional for pain management, excessive polypharmacy (≥10 medications), and use of cannabis for pain.

Results

1,399 participants completed the questionnaire (women: 83.4%, mean age: 50 years, living in remote regions: 23.8%). As compared to persons living in remote regions, those living in non-remote regions were more likely to report using prescribed pain medications (83.8% vs. 67.4%), a multimodal approach (81.5% vs. 75.5%), experience excessive polypharmacy (28.1% vs. 19.1%), and report using cannabis for pain (33.1% vs. 20.7%) (bivariable p < 0.05). Only the use of prescribed medications as well as cannabis remained significantly associated with the region of residence in the multivariable models.

Discussion

There are differences in treatment profiles of persons with CP depending on the region they live. Our results highlight the importance of considering remoteness, and not only rurality, when it comes to better understanding the determinants of pain management.

The Medication Quantification Scale 4.0: An Updated Index Based on Prescribers' Perceptions of the Risk Associated With Chronic Pain Medications

To quantify risks associated with drug utilization in the real world for the treatment of chronic pain (CP), an index called the Medication Quantification Scale (MQS) was developed in 1992 in the United States and last updated in 2003. This study aimed to update, adapt to the contemporary Canadian context, and validate a revised version of the MQS (the MQS-4.0). Step 1: An expert committee adapted the MQS to the Canadian clinical practice context. Step 2: An update of risk weights given to medication subclasses was achieved using a prescriber survey (weights were derived from median 0-10 scores given to each subclass). Step 3: Construct validity of the MQS-4.0 was assessed after applying risk weights to the medication use profile of persons living with CP covered by public drug insurance plan. Thirty-six medication subclasses were included in the MQS-4.0. A total of 207 prescribers (physicians, pharmacists, and nurse practitioners) participated in the perception survey; 10.63% identified as pain specialists. When risk weights were applied to prescription claims (n = 9,122), the MQS-4.0 score was associated (P < .05) with the MQS-III score and variables associated with polypharmacy (eg, Charlson Comorbidity Index, number of prescribers or health care visits). This study provides an updated index intended for adult populations based on prescribers' perceptions of the risk associated with CP medications that can be useful for clinical practice and research among persons living with CP in Canada. It will, however, be relevant to verify whether similar risk weights are obtained in future pain specialist surveys. PERSPECTIVE: The MQS-4.0 is an update of the MQS used for quantifying the risk associated with the use of analgesics/coanalgesics. Adequate psychometrics properties were found.

Therapeutic Potential of Downregulated Interleukin-6 Signaling for the Treatment of Chronic Pain: A Mendelian Randomization Study

Introduction

While numerous studies have emphasized the pivotal involvement of the Interleukin 6 (IL-6) pathway in the development of chronic pain, the causal nature of this relationship remains uncertain.

Methods

In this study, we opted to include genetic variants situated within the locus of the IL-6 receptor (IL-6R) that exhibited associations with C-reactive protein (CRP) levels. CRP serves as a downstream effector in the IL-6 pathway. Utilizing these variants as genetic proxies, we aimed to modulate IL-6 signaling. Employing a two-sample Mendelian randomization (MR) approach, we investigated the potential link between the genetic proxy and seven distinct subtypes of chronic pain, categorized based on their corresponding body locations. Moreover, we examined the relationship between chronic pain and an alternative instrument of IL-6 signaling that was weighted based on s-IL-6R levels. Furthermore, we conducted exploratory analyses to estimate the plausible causal association between CRP, gp130, and the subtypes of chronic pain.

Results

Our analysis showed that genetic proxied downregulation of IL-6 signaling, weighted on CRP levels, was linked to a reduced risk of chronic back and knee pain. The sensitivity analyses across various MR methods confirmed the consistency of the findings and showed no evidence of horizontal pleiotropy or heterogeneity. Moreover, the results remained robust with different sets of instrument variables. A genetically increased level of s-IL-6R was also negatively associated with chronic back and knee pain. However, there was no causal relationship between CRP and gp130 with chronic pain.

Conclusion

Based on our findings, there is evidence to suggest a potential causal relationship between IL-6 signaling and chronic back and knee pain. Consequently, the downregulation of IL-6 signaling holds promise as a potential therapeutic target for addressing chronic back and knee pain.

Physicians' perception about predictors of opioid abuse in patients with chronic non-cancer pain: a Delphi study

Background

Opioids are being prescribed widely, and increasingly, for the treatment of chronic non-cancer pain (CNCP). However, several side effects are associated with mid- and long-term opioid use and, for certain patients, with the risk of problematic opioid use. The aim of this study is to know the perception of the physicians about which variables could be associated with increased risk of patients with CNCP developing a problem of abuse or misuse of the prescribed opioid medication.

Methods

Twenty-nine physicians with experience in CNCP pain management and opioids prescription participated in a two-round Delphi study focused on the risk factors for opioid misuse and abuse.

Results

The variables that reached consensus regarding their relationship with the increased risk of suffering a problem of opioid abuse or misuse were: (1) Experiencing pain on a daily basis, (2) previous use of high-dose opioids, (3) generalized anxiety, (4) hopelessness, (5) benzodiazepine intake, (6) use of opioids for reasons other than pain, (7) family problems, family instability or family breakdown, and (8) having access to several opioid prescribers. The only variable that reached consensus regarding it not being associated to a possible risk of abuse or misuse was having mild pain intensity (0-4 on a NRS-11).

Conclusions

This study provides useful information that could help make decisions about the use of opioids for CNCP treatment and prevent future difficulties. Prospective studies testing the relationship of the variables that reached consensus with the risk of opioid misuse and abuse are warranted.

Significance

This study shows the variables of CNCP that the professional must take into account in order to avoid possible problems when prescribing opioids.

Perceptions and Preoccupations of Patients and Physicians Regarding Use of Medical Cannabis as an Intervention Against Chronic Musculoskeletal Pain: Results from a Qualitative Study

Objective

Explore perceptions and preoccupations regarding use of medical cannabis against chronic musculoskeletal pain, among patients and physicians.

Design

Qualitative study using interviews with patients and physicians, based on the Theory of Planned Behavior (TPB).

Setting

The study was conducted in Quebec, Canada, in spring 2020.

Subjects

We included 27 adult patients and 11 physicians (GPs, anesthesiologists, psychiatrists, and a rheumatologist); the mean age of patients was 48.2 years; 59.3% of patients and 36.4% of physicians were women; 59.3% of patients used no medical cannabis at the time of study; 45.5% of physicians had never authorized it.

Methods

Semi-structured interviews were conducted, transcribed and for the qualitative analysis codes were developed in a hybrid, inductive and deductive approach. Guided by the TPB, facilitators and barriers, perceived benefits and harms, and perceived norms that may influence cannabis use or authorization were documented.

Results

Although medical cannabis is an interesting avenue for the relief of chronic musculoskeletal pain, doctors and patients agreed that it remained a last line option, due to the lack of scientific evidence regarding its safety and efficacy. The norms surrounding medical cannabis also play an important role in the social and professional acceptance of this therapeutic option.

Conclusion

Medical cannabis is seen as a last line option among interventions in the management of chronic pain, and attitudes and prior experiences play a role in the decision to use it. Study results may contribute to improved shared decision making between patients and physicians regarding this option.

Gender differences in PTSD severity and pain outcomes: baseline results from the LAMP trial

Background

Post-traumatic stress disorder (PTSD) and chronic pain are highly prevalent comorbid conditions. Veterans dually burdened by PTSD and chronic pain experience more severe outcomes compared to either disorder alone. Few studies have enrolled enough women Veterans to test gender differences in pain outcomes [catastrophizing, intensity, interference] by the severity of PTSD.

Aim

Examine gender differences in the association between PTSD symptoms and pain outcomes among Veterans enrolled in a chronic pain clinical trial.

Methods

Participants were 421 men and 386 women Veterans with chronic pain who provided complete data on PTSD symptoms and pain outcomes. We used hierarchical linear regression models to examine gender differences in pain outcomes by PTSD symptoms.

Results

Adjusted multivariable models indicated that PTSD symptoms were associated with higher levels of pain catastrophizing (0.57, 95% CI [0.51, 0.63]), pain intensity (0.30, 95% CI [0.24, 0.37]), and pain interference (0.46, 95% CI [0.39, 0.52]). No evidence suggesting differences in this association were found in either the crude or adjusted models (all interaction p-values<0.05).

Conclusion

These findings may reflect the underlying mutual maintenance of these conditions whereby the sensation of pain could trigger PTSD symptoms, particularly if the trauma and pain are associated with the same event. Clinical implications and opportunities testing relevant treatments that may benefit both chronic pain and PTSD are discussed.

Polypharmacy and Excessive Polypharmacy Among Persons Living with Chronic Pain: A Cross-Sectional Study on the Prevalence and Associated Factors

Purpose

Polypharmacy can be defined as the concomitant use of ≥5 medications and excessive polypharmacy, as the use of ≥10 medications. Objectives were to (1) assess the prevalence of polypharmacy and excessive polypharmacy among persons living with chronic pain, and (2) identify sociodemographic and clinical factors associated with excessive polypharmacy.

Patients and Methods

This cross-sectional study used data from 1342 persons from the ChrOnic Pain trEatment (COPE) Cohort (Quebec, Canada). The self-reported number of medications currently used by participants (regardless of whether they were prescribed or taken over-the-counter, or were used for treating pain or other health issues) was categorized to assess polypharmacy and excessive polypharmacy.

Results

Participants reported using an average of 6 medications (median: 5). The prevalence of polypharmacy was 71.4% (95% CI: 69.0-73.8) and excessive polypharmacy was 25.9% (95% CI: 23.6-28.3). No significant differences were found across gender identity groups. Multivariable logistic regression revealed that factors associated with greater chances of reporting excessive polypharmacy (vs <10 medications) included being born in Canada, using prescribed pain medications, and reporting greater pain intensity (0-10) or pain relief from currently used pain treatments (0-100%). Factors associated with lower chances of excessive polypharmacy were using physical and psychological pain treatments, reporting better general health/physical functioning, considering pain to be terrible/feeling like it will never get better, and being employed.

Conclusion

Polypharmacy is the rule rather than the exception among persons living with chronic pain. Close monitoring and evaluation of the different medications used are important for all persons, especially those with limited access to care.

A systematic review of genome-wide association studies for pain, nociception, neuropathy, and pain treatment responses

ABSTRACT

Pain is the leading cause of disability worldwide, imposing an enormous burden on personal health and society. Pain is a multifactorial and multidimensional problem. Currently, there is (some) evidence that genetic factors could partially explain individual susceptibility to pain and interpersonal differences in pain treatment response. To better understand the underlying genetic mechanisms of pain, we systematically reviewed and summarized genome-wide association studies (GWASes) investigating the associations between genetic variants and pain/pain-related phenotypes in humans. We reviewed 57 full-text articles and identified 30 loci reported in more than 1 study. To check whether genes described in this review are associated with (other) pain phenotypes, we searched 2 pain genetic databases, Human Pain Genetics Database and Mouse Pain Genetics Database. Six GWAS-identified genes/loci were also reported in those databases, mainly involved in neurological functions and inflammation. These findings demonstrate an important contribution of genetic factors to the risk of pain and pain-related phenotypes. However, replication studies with consistent phenotype definitions and sufficient statistical power are required to validate these pain-associated genes further. Our review also highlights the need for bioinformatic tools to elucidate the function of identified genes/loci. We believe that a better understanding of the genetic background of pain will shed light on the underlying biological mechanisms of pain and benefit patients by improving the clinical management of pain.

Trends in Prescription Chronic Pain Medication Use before and during the First Wave of the COVID-19 Pandemic in Québec, Canada: An Interrupted Time Series Analysis

BACKGROUND

In Canada, a state of health emergency was declared in May 2020 as a result of the COVID-19 pandemic. This study aimed to assess trends in the use of prescription medication for pain management by people living with chronic pain before and during the first wave of the pandemic.

METHODS

Participants (n = 177) were adults reporting chronic pain who had completed a web-based questionnaire in 2019 and for whom complete longitudinal private and public insurance prescription claims were available. The monthly prevalence of medication use for nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, and prescribed cannabinoids was assessed. An interrupted time series analysis was then performed to evaluate if the COVID-19 pandemic had had an impact on trends in pain medication use.

RESULTS

The beginning of the first wave of the pandemic was associated with the onset of a downward trend in opioid use (p < 0.05); no such association was found regarding NSAIDs. However, point prevalence of opioid use at the beginning (Nov. 2019) and at the end (Mai 2020) of the study period remained somewhat stable (17.0% vs. 16.4%). Regarding prescribed cannabinoids, a gradual increase in use was observed over the entire study period independently from the impact of the first wave of the pandemic (15.3% vs. 22.6%, p < 0.05).

CONCLUSION

While the occurrence of the first wave did have an impact on opioid use among people living with chronic pain, access to and use of opioids appear to have returned to normal before the end of the first wave of COVID-19.

Sex differences in patient journeys to diagnosis, referral, and surgical treatment of trigeminal neuralgia: implications for equitable care

OBJECTIVE

Trigeminal neuralgia (TN) is an orofacial pain disorder that is more prevalent in females than males. Although an increasing number of studies point to sex differences in chronic pain, how sex impacts TN patients' journeys to care has not been previously addressed. This study sought to investigate sex differences in patients' journeys to diagnosis, referral, and treatment of TN within a large national context.

METHODS

Patients with classic TN (n = 100; 50 females and 50 males) were randomly selected through chart reviews at the largest surgical treatment center for TN in Canada for a cross-sectional study. Statistical tests, including Welch's t-test, the chi-square test, Pearson's correlations, and analyses of covariance, were conducted with Python.

RESULTS

Key discrepancies between sexes in access to care were identified. Females had a significantly longer referral time interval (average 53.2 months vs 20.4 months, median 27.5 months vs 11.0 months, p = 0.018) and total time interval (average 121.1 months vs 67.8 months, median 78.0 months vs 45.2 months, p = 0.018) than males, despite reporting higher pain intensity at referral. Although medically intolerant patients had a significantly shorter referral time interval than medically tolerant patients (average 13.0 months vs 41.0 months, median 6.0 months vs 17.0 months, p < 0.001), medically tolerant females had a significantly longer referral time interval than medically tolerant males (average 59.9 months vs 21.7 months, median 30.0 months vs 12.0 months, p = 0.017). No statistically significant differences were detected between the sexes for diagnostic time interval (average 63.3 months vs 43.0 months, median 24.0 months vs 24.0 months, p = 0.263) or treatment time interval (average 4.6 months vs 4.7 months, median 4.0 months vs 3.0 months, p = 0.986).

CONCLUSIONS

Critical sex differences in patients' journeys to TN surgical treatment were identified, with females enduring considerably longer referral timelines and expressing significantly greater pain intensity than males at referral. Taken together, our findings suggest the presence of unconscious bias and discrimination against females and highlight the need for expediting TN treatment referral for female TN patients.

Sex and gender differences in healthcare utilisation trajectories: a cohort study among Quebec workers living with chronic pain

OBJECTIVES

Chronic pain (CP) is a poorly recognised and frequently inadequately treated condition affecting one in five adults. Reflecting on sociodemographic disparities as barriers to CP care in Canada was recently established as a federal priority. The objective of this study was to assess sex and gender differences in healthcare utilisation trajectories among workers living with CP.

DESIGN

Retrospective cohort study.

PARTICIPANTS

This study was conducted using the TorSaDE Cohort which links the 2007-2016 Canadian Community Health Surveys and Quebec administrative databases (longitudinal claims). Among 2955 workers living with CP, the annual number of healthcare contacts was computed during the 3 years after survey completion.

OUTCOME

Group-based trajectory modelling was used to identify subgroups of individuals with similar patterns of healthcare utilisation over time (healthcare utilisation trajectories).

RESULTS

Across the study population, three distinct 3-year healthcare utilisation trajectories were found: (1) low healthcare users (59.9%), (2) moderate healthcare users (33.6%) and (3) heavy healthcare users (6.4%). Sex and gender differences were found in the number of distinct trajectories and the stability of the number of healthcare contacts over time. Multivariable analysis revealed that independent of other sociodemographic characteristics and severity of health condition, sex-but not gender-was associated with the heavy healthcare utilisation longitudinal trajectory (with females showing a greater likelihood; OR 2.6, 95% CI 1.6 to 4.1).

CONCLUSIONS

Our results underline the importance of assessing sex-based disparities in help-seeking behaviours, access to healthcare and resource utilisation among persons living with CP.

High-dose opioids for chronic non-cancer pain: an overview of Cochrane Reviews

BACKGROUND

This overview was originally published in 2017, and is being updated in 2022.  Chronic pain is typically described as pain on most days for at least three months. Chronic non-cancer pain (CNCP) is any chronic pain that is not due to a malignancy. Chronic non-cancer pain in adults is a common and complex clinical issue, for which opioids are prescribed by some physicians for pain management. There are concerns that the use of high doses of opioids for CNCP lacks evidence of effectiveness, and may increase the risk of adverse events.

OBJECTIVES

To describe the evidence from Cochrane Reviews and overviews regarding the efficacy and safety of high-dose opioids (defined as 200 mg morphine equivalent or more per day) for CNCP.

METHODS

We identified Cochrane Reviews and overviews by searching the Cochrane Database of Systematic Reviews in The Cochrane Library. The date of the last search was 21 July 2022. Two overview authors independently assessed the search results. We planned to analyse data on any opioid agent used at a high dose for two weeks or more for the treatment of CNCP in adults.

MAIN RESULTS

We did not identify any reviews or overviews that met the inclusion criteria. The excluded reviews largely reflected low doses or titrated doses, where all doses were analysed as a single group; we were unable to extract any data for high-dose use only.

AUTHORS' CONCLUSIONS

There is a critical lack of high-quality evidence, in the form of Cochrane Reviews, about how well high-dose opioids work for the management of CNCP in adults, and regarding the presence and severity of adverse events.  No evidence-based argument can be made on the use of high-dose opioids, i.e. 200 mg morphine equivalent or more daily, in clinical practice. Considering that high-dose opioids have been, and are still being used in clinical practice to treat CNCP, knowing about the efficacy and safety of these higher doses is imperative.

The dose-dependent effects of transcutaneous electrical nerve stimulation for pain relief in individuals with fibromyalgia: a systematic review and meta-analysis

ABSTRACT

Transcutaneous electrical nerve stimulation (TENS) is a nonpharmacological modality widely used to manage pain; however, its effectiveness for individuals with fibromyalgia (FM) has been questioned. In previous studies and systematic reviews, variables related to dose of TENS application have not been considered. The objectives of this meta-analysis were (1) to determine the effect of TENS on pain in individuals with FM and (2) determine the dose-dependent effect of TENS dose parameters on pain relief in individuals with FM. We searched the PubMed, PEDro, Cochrane, and EMBASE databases for relevant manuscripts. Data were extracted from 11 of the 1575 studies. The quality of the studies was assessed using the PEDro scale and RoB-2 assessment. This meta-analysis was performed using a random-effects model that, when not considering the TENS dosage applied, showed that the treatment had no overall effect on pain (d+ = 0.51, P > 0.050, k = 14). However, the moderator analyses, which were performed assuming a mixed-effect model, revealed that 3 of the categorical variables were significantly associated with effect sizes: the number of sessions (P = 0.005), the frequency (P = 0.014), and the intensity (P = 0.047). The electrode placement was not significantly associated with any effect sizes. Thus, there is evidence that TENS can effectively reduce pain in individuals with FM when applied at high or at mixed frequencies, a high intensity, or in long-term interventions involving 10 or more sessions. This review protocol was registered at PROSPERO (CRD42021252113).

Association between urinary phthalate levels and chronic pain in US adults, 1999-2004: A nationally representative survey

Introduction

Chronic pain is a public health concern throughout the world. Ascertaining and managing its risk factors helps develop well-directed treatment plans and prevention strategies. Phthalates (PAEs) exposure leads to various health problems. The present study aims to explore the potential correlation between urinary PAEs metabolites and chronic pain in adults.

Methods

The study population data were extracted from the National Health and Nutrition Examination Survey (NHANES) conducted from 1999 to 2004 in the United States. Seven urinary PAEs metabolites were used to assess long-term PAEs exposure. The assessment of chronic pain was determined by a self-report questionnaire. Weighted analyses were conducted to consider the complex sampling design. Models were adjusted by demographic data and lifestyle factors. Urinary PAEs metabolites were assessed as both continuous and categorical variables. Tertile 1 was considered as the reference. Stratified analyses were performed by gender and pain site. All data analyses were conducted with STATA, version 15.1. P < 0.05 was considered with statistical significance.

Results

A total of 4,196 participants were considered in our final analysis. Chronic pain prevalence reached 52.19% (n = 2,138) among the participants, with women accounting for a large proportion (57.75% vs. 42.25%). After multivariable logistic regression analysis, a higher prevalence of chronic pain was observed among participants in the third tertile of mono-(2-ethyl)-hexyl phthalate (MEHP) (OR = 1.23, 95% CI = 1.02-1.48, P = 0.034) and mono-benzyl phthalate (MBzP) (OR = 1.28, 95% CI = 1.04-1.58, P = 0.022) in our adjusted model. The logtransformed concentration of MBzP also showed a significant association with chronic pain prevalence (OR = 1.09, 95% CI = 1.01-1.18, P = 0.036) in the adjusted model. In further analysis, the positive correlations of urinary phthalate metabolites with chronic pain remained robust when stratified by gender and chronic pain site.

Conclusions

Our findings presented a positive correlation between urinary PAEs metabolites and chronic pain among adult participants, and more causal research should be conducted to ascertain the interactions between the two and to expound their underlying mechanisms.

Effects of ethanol on mechanical allodynia and dynamic weight bearing in male and female mice with spared nerve injury

BACKGROUND

Men and women with chronic pain report increased alcohol use and are more likely to be diagnosed with alcohol use disorder. The relationship between alcohol use and pain is bidirectional. Alcohol is used as an analgesic, but chronic alcohol intake increases pain. Sex differences in the relationship between chronic pain and alcohol are reported in the clinical and preclinical literature, but due to this bidirectional relationship, it is challenging to investigate the mechanisms that contribute to these differences. Thus, animal models of chronic pain are needed to characterize the efficacy of ethanol as an analgesic in males and females. The current experiments tested the hypothesis that ethanol differentially reduces pain behaviors in male and female mice in chronic neuropathic pain.

METHODS

The spared nerve injury (SNI) model was used to investigate the analgesic effects of multiple doses of ethanol (0.5, 1, 2, g/kg i.p.) in male and female mice using von Frey and dynamic weight-bearing (DWB) assays.

RESULTS

In both male and female mice, SNI led to robust allodynia and shifts in dynamic weight bearing. In male SNI mice, all three doses of ethanol fully reversed mechanical allodynia and shifts in DWB. In SNI females, only the highest dose (2.0 g/kg) was fully antiallodynic in the von Frey assay, while shifts in weight bearing were reversed at the 1.0 and 2.0 g/kg doses. The differences between male and females were not due to lower blood ethanol concentrations in female mice.

CONCLUSION

These data indicate that while ethanol has antiallodynic and antinociceptive effects in male and female mice, the doses and time course of these effects are distinct. Studies investigating the relationship between pain and ethanol exposure in mice should consider sex as a key variable. These data also inform reported sex differences in rodent models of chronic pain and in chronic pain patients.

Factors associated with frequent or daily use of prescription opioids among adults with chronic pain in the United States

OBJECTIVES

We aimed to estimate utilization rates of prescription opioids among adults with chronic pain in the United States (US) and identify factors associated with the frequent or daily use of prescription opioids.

METHODS

This was a case-control analysis of the 2019 National Health Interview Survey of adults.

RESULTS

Over 50.2 million adults in the US reported chronic pain in the past 3 months, but only 10.5% of this group said they used prescription opioids frequently or daily to manage their pain. Adults with chronic pain were significantly more likely to use opioids if they had incomes below the federal poverty level (15.7%), relied on public health insurance (14.8%), had been hospitalized in the past year (17.8%), or rated their health as fair or poor (18.4%). The highest rates of opioid use were reported among adults with severe (24.4%) or moderate disability (18.9%).

CONCLUSIONS

Approximately 5.3 million adults use prescription opioids frequently or daily to manage chronic pain. These individuals should receive regular clinical assistance to manage their pain, including medication management and, when appropriate, referral to evidence-based treatment programs for opioid use disorder.

AdipoRon Engages Microglia to Antinociception through the AdipoR1/AMPK Pathway in SNI Mice

Background

Microglia-associated neuroinflammation plays a crucial role in the initiation and development of neuropathic pain (NeuP). AdipoRon is an analog of adiponectin that exerts an anti-inflammatory effect in various diseases through the adiponectin receptor 1 (AdipoR1) signaling mechanism. Adenosine monophosphate-activated protein kinase (AMPK) is a downstream target of AdipoR1, and the AdipoR1/AMPK pathway is involved in the regulation of inflammation. This study is aimed at investigating whether AdipoRon could alleviate NeuP by inhibiting the expression of microglia-derived tumor necrosis factor-alpha (TNF-α) through the AdipoR1/AMPK pathway.

Methods

In vivo, the NeuP model was established in mice through the spared nerve injury. The von Frey test was used to detect the effect of AdipoRon on the mechanical paw withdrawal threshold. Western Blot was performed to detect the effects of AdipoRon on the expression of TNF-α, AdipoR1, AMPK, and p-AMPK. Immunofluorescence was performed to observe the effects of AdipoRon on spinal microglia. In vitro, lipopolysaccharide (LPS) was used to induce inflammatory responses in BV2 cells. The effect of AdipoRon on cell proliferation was detected by CCK-8. qPCR was used to examine the effects of AdipoRon on the expression of TNF-α and polarization markers. And the effect of AdipoRon on the AdipoR1/AMPK pathway was confirmed by Western Blot.

Results

Intraperitoneal injection of AdipoRon alleviated mechanical nociception in SNI mice, and the application of AdipoRon reduced the expression of TNF-α and the number of microglia in the ipsilateral spinal cord. Additionally, AdipoRon decreased the protein level of AdipoR1 and increased the protein level of p-AMPK in the ipsilateral spinal cord. In vitro, AdipoRon inhibited BV2 cell proliferation and reversed LPS-induced TNF-α expression and polarization imbalance. Furthermore, AdipoRon reversed the LPS-induced increase in AdipoR1 expression and decrease in p-AMPK expression in BV2 cells.

Conclusions

AdipoRon may alleviate NeuP by reducing microglia-derived TNF-α through the AdipoR1/AMPK pathway.

Reliability and aspects of validity of the Swedish version of self-efficacy for exercise scale for patients with chronic pain

BACKGROUND

Active, specific, and professionally led physical exercise is an effective treatment for chronic pain, and self-efficacy is correlated to positive treatment outcomes. At present, there is limited knowledge of self-efficacy for exercise in patients with chronic pain.

PURPOSE

To evaluate the reliability and aspects of validity of the Swedish version of the Self-Efficacy for Exercise Scale (SEE-SV) in patients with chronic pain.

METHODS

Patients with chronic pain were recruited from a specialist clinic. The Swedish version of the SEE was used. Reliability was evaluated through internal consistency, test-retest, and measurement error (standard error of measurement, SEM and smallest detectable change, SDC). Construct validity was calculated using the correlation between the SEE-SV and other well-established evaluation instruments. Content validity was evaluated both from a patient and a health-care professional perspective.

RESULTS

In total, 44 patients, 31 women and 13 men (mean age 40 years), participated in the study. The SEE-SV had good test-retest reliability (intra-class correlation coefficient (ICC) = 0.95) and internal consistency (Cronbach's alpha = 0.97). Regarding measurement error, SEM was 4.9 and SDC 13.5. Moderate correlation was seen between SEE-SV and a pain-specific self-efficacy questionnaire (rs = 0.52). The majority of patients and health-care professionals considered the SEE-SV to be relevant and easy to understand.

CONCLUSION

The SEE-SV showed a good internal consistency, item-to-total correlation, and test-retest reliability (ICC). A relatively high SDC indicates an individual variability of the test results. The content validity was satisfactory. Regarding the construct validity, further studies are needed.

Factors affecting chronic low back pain among high school baseball players in Japan: A pilot study

The prevalence of chronic lower back pain (CLBP) among baseball players is high. CLBP is associated with reduced participation in practice and games. This pilot study examined the factors associated with CLBP among high school baseball players in Fukui, Japan. The participants underwent two health examinations in high school: (1) as first-grade baseball players (baseline) and (2) as second-grade baseball players (follow-up); a total of 59 players who could be followed-up a year later were included in the study. Players were divided into three groups based on whether they had no lower back pain (LBP) (n = 30), improved LBP (n = 17), or CLBP (n = 12) after 1 year of follow-up. Players were evaluated on the physical and cognitive aspects of pain. The Number Rating System, Pain Catastrophizing Scale (PCS), Tampa Scale for Kinesiophobia (TSK), Central Sensitization Inventory (CSI), body characteristics (age, height, weight, body mass index, and skeletal mass index), and a medical history questionnaire regarding spondylolysis and baseball loads were used to evaluate the players. Inventory scores were highest in the CLBP group, which indicated that this group had significant pain that affected their willingness to engage in baseball-related activities. The TSK scores in the CLBP group were worse on follow-up. High school baseball players with CLBP were more likely to have lumbar spondylolysis and kinesiophobia, which are also factors related to pain chronicity. Kinesiophobia and the presence of lumbar spondylolysis should be considered when creating an exercise program for high school baseball players with CLBP.

How do peer support interventions for the self-management of chronic pain, support basic psychological needs? A systematic review and framework synthesis using self-determination theory

OBJECTIVE

To identify how peer support interventions, for self-management of chronic pain, support basic psychological needs from a self-determination theory (SDT) perspective, using a systematic review.

METHODS

Ten databases were searched for studies reporting qualitative research about peer interactions in pain management interventions. 'Best fit' framework synthesis methodology was applied to identify strategies that support the satisfaction of competence, autonomy and motivation. These were matched to definitions of strategies provided by standardised taxonomies.

RESULTS

18 studies were selected for inclusion. The synthesis resulted in a conceptual model, identifying 12 peer strategies that support psychological needs for self-management of chronic pain; 10 overlapped with existing taxonomies.

CONCLUSION

This was the first known attempt to synthesise evidence about peer support strategies for people living with pain, using SDT as an a priori framework. The model demonstrates commonality between the motivation-promoting processes of peer support and those of other behaviour change interventions and identifies additional unique strategies provided by peers. This systematic classification of peer support strategies provides a means for future study of the efficacy and comprehensiveness of peer interventions.

PRACTICE IMPLICATIONS

The model could assist healthcare professionals and support groups to optimise the potential of peer processes.

The correlation between illness perception, pain intensity and quality of life in elderly with low back pain in Denmark: a cross-sectional study

Background

Illness perception is related to management patterns and pain intensity, but among elderly with low back pain, this relation is unclear. The aims of this study were to analyse the associations between illness perception, pain intensity and health related quality of life in a group of elderly with low back pain and explore how different illness perception profiles would cluster and differ in terms of pain, quality of life and choice of management.

Method

This was a cross-sectional survey based on a cohort of originally 640 Danish children. Of the 311 respondents in 2019, 69% reported low back pain within last year and were included. Associations between illness perceptions (Brief illness perception questionnaire), health related quality of life (EuroQol-5 Domain-3L) and low back pain intensity were assessed, and participants were clustered based on their perceptions using hierarchical and K-means cluster analysis. Cluster differences in pain, quality of life and use of pharmacological and non-pharmacological treatments were explored.

Results

Among the 213 individuals with low back pain, 33% reported severe or fluctuating pain intensity. Higher pain intensity was associated with perceiving low back pain as a greater threat. Participants reporting fluctuating pain perceived their low back pain almost as threatening as participants reporting severe pain. Two clusters were identified. Cluster 1 reported lower quality of life (difference in medians: -0.176 (95% CI [-0.233--0.119 ])) and was more likely to report severe or fluctuating pain (37.7% vs. 4.5% [P < 0.0001]) and to use pharmacological treatments than Cluster 2 (37.7% vs. 14.9% [P < 0.001]). No association was found between clusters concerning use of non-pharmacological treatments (P = 0.134).

Conclusion

Based on illness perceptions, two clusters differing in pain intensity, quality of life and use of pharmacological treatments were identified. Targeting illness perceptions may be beneficial during rehabilitation or when guiding patients with low back pain in choice of management.

Association between opioid therapy trajectories and potential opioid-related adverse health events

PURPOSE

We identified associations between membership in seven group-based trajectories based on supply of filled opioid prescriptions and potential opioid-related adverse health events over a 720-day window.

METHODS

We identified two veteran cohorts with chronic non-cancer pain who initiated treatment with long-term opioid therapy between 2008 and 2015, excluding those with prior substance use disorder (n = 373 941) or non-SUD, opioid-related adverse outcome (n = 405 631) diagnoses. Outcomes of interest included opioid use disorder, non-opioid drug use disorder, and alcohol use disorder for the first cohort; or accidents resulting in wounds or injuries, self-inflicted injuries, opioid-related accidents and overdoses, alcohol and non-opioid drug-related accidents and overdoses, and violence-related injuries for the second cohort. Using a cross-sectional design, Veterans were followed until the specific outcome of interest was diagnosed, they died, the study ended, or they were lost to follow up. Accelerated failure time models were estimated for each outcome.

RESULTS

Membership in persistent moderate days covered and persistent modest days covered trajectories was associated with decreased risk of opioid use disorder (Moderate: θ = 0.59, 95%CI:0.54, 0.64; Modest: θ = 0.54, 95%CI:0.50, 0.59) and opioid overdose (Moderate: θ = 0.67,95%CI: 0.57, 0.79; Modest: θ = 0.72, 95%CI:0.61, 0.85) versus higher-utilizing persistent users. Rapid discontinuation was associated with decreased risk of opioid use disorder (θ = 0.86, 95% CI:0.77, 0.95) and opioid overdose (θ = 0.54, 95%CI:0.41, 0.71), but increased risk of alcohol use disorder (θ = 1.07, 95%CI:1.00, 1.15) and other substance use disorders. Delayed discontinuation or delayed reduction was associated with increased risk for most opioid related adverse health events.

CONCLUSION

Persistent use trajectories with low levels of opioid utilization were associated with lower risks of potential opioid-related adverse health events.

Transcutaneous electrical nerve stimulation effects on pain-intensity and endogenous opioids levels among chronic low-back pain patients: A randomised controlled trial

BACKGROUND

Transcutaneous electrical nerve stimulation (TENS) is a promising non-pharmacological modality for the management of chronic low back pain (CLBP), but its efficacy and mode of action have not been clearly established.

OBJECTIVE

To evaluate the responses of plasma beta-endorphin (βE), met-enkephalin (ME), and pain intensity (PI) among patients with CLBP exposed to TENS or sham-TENS.

METHODS

This double-blind trial involved 62 participants (aged 53.29 ± 5.07 years) randomised into TENS group (frequency 100 Hz, burst-rate 2 Hz, burst-width 150 μs, intensity 40 mA, duration 30 min), and sham-TENS group. The PI and plasma concentrations of βE and ME were measured at baseline, immediately (0 hr), 1 hr, 24 hrs, and 48 hrs post-intervention. Data were analysed using general linear model repeated measures, ordinal regression, one-way analysis of variance, Kruskal-Wallis test, independent and paired samples t-tests, Mann-Whitney U test, Wilcoxon signed-rank test, and Kendall's tau coefficient.

RESULTS

There was a significant temporal difference in PI between groups, F (1, 58) = 18.83, p< 0.001; the TENS group had better pain relief. The relative analgesic effect of TENS started immediately after the intervention (median difference [M⁢D] =-3, p< 0.001), peaked at 1 hr (M⁢D=-4, p< 0.001), and worn out by 24 hrs (M⁢D=-1, p= 0.029). However, there was no significant difference in βE and ME between the groups from 0 hr to 24 hrs post interventions, and no significant correlation between the PI, and βE, or ME.

CONCLUSION

TENS significantly reduced PI up to 24 hrs after treatment.

Opioid epidemic: lessons learned and updated recommendations for misuse involving prescription versus non-prescription opioids

INTRODUCTION

In the past decades, the opioid crisis has heavily impacted parts of the US society and has been followed by an increase in the use of opioids worldwide. It is of paramount importance that we explore the origins of the US opioid epidemic to develop best practices to tackle the rising tide of opioid overdoses.

AREAS COVERED

In this expert review, we discuss opioid (over)prescription, change in perception of pain, and false advertisement of opioid safety as the leading causes of the US opioid epidemic. Then, we review the evidence about opioid dependence and addiction potential and provide current knowledge about predictors of aberrant opioid-related behavior. Lastly, we discuss different approaches that were considered or undertaken to combat the rising tide of opioid-related deaths by regulatory bodies, pharmaceutical companies, and health-care professionals. For this expert review, we considered published articles relevant to the topic under investigation that we retrieved from Medline or Google scholar electronic database.

EXPERT OPINION

The opioid epidemic is a dynamic process with many underlying mechanisms. Therefore, no single approach may be best suited to combat it. In our opinion, the best way forward is to employ multiple strategies to tackle different underlying mechanisms.

Determining the Influencing Factors on Acceptance of eHealth Pain Management Interventions Among Patients With Chronic Pain Using the Unified Theory of Acceptance and Use of Technology: Cross-sectional Study

Background

Chronic pain is a complex disease with high prevalence rates, and many individuals who are affected do not receive adequate treatment. As a complement to conventional therapies, eHealth interventions could provide many benefits to a multimodal treatment approach for patients with chronic pain, whereby future use is associated with the acceptance of these interventions.

Objective

This study aims to assess the acceptance of eHealth pain management interventions among patients with chronic pain and identify the influencing factors on acceptance. A further objective of the study is to evaluate the viability of the Unified Theory of Acceptance and Use of Technology (UTAUT) model and compare it with its extended version in terms of explained variance of acceptance.

Methods

We performed a cross-sectional web-based study. In total, 307 participants with chronic pain, as defined according to the International Association for the Study of Pain criteria, were recruited through flyers, posters, and web-based inquiries between December 2020 and July 2021. In addition to sociodemographic and medical data, the assessment included validated psychometric instruments and an extended version of the well-established UTAUT model. For statistical analyses, group comparisons and multiple hierarchical regression analyses were performed.

Results

The acceptance of eHealth pain management interventions among patients with chronic pain was overall moderate to high (mean 3.67, SD 0.89). There was significant difference in acceptance among age groups (W=9674.0; r=0.156; P=.04). Effort expectancy (β=.37; P<.001), performance expectancy (β=.33; P<.001), and social influence (β=.34; P<.001) proved to be the most important predictors of acceptance. The extended UTAUT (including the original UTAUT factors as well as sociodemographic, medical, and eHealth-related factors) model explained 66.4% of the variance in acceptance, thus supporting the viability of the model. Compared with the original UTAUT model (performance expectancy, effort expectancy, and social influence), the extended model explained significantly more variance (F_25,278=1.74; P=.02).

Conclusions

Given the association between acceptance and future use, the knowledge of the influencing factors on acceptance should be used in the development and promotion of eHealth pain management interventions. Overall, the acceptance of eHealth pain management interventions was moderate to high. In total, 8 predictors proved to be significant predictors of acceptance. The UTAUT model is a valuable instrument for determining acceptance as well as the factors that influence acceptance of eHealth pain management interventions among patients with chronic pain. The extended UTAUT model provided the greatest predictive value for acceptance.

Discordance in Addressing Opioid Crisis in Rural Communities: Patient and Provider Perspectives

Providing patient-centered care to manage chronic pain and opioid use disorder (OUD) is associated with improved health outcomes. However, adopting a holistic approach to providing care is often challenging in rural communities. This study aims to identify and contrast challenges to providing patient-centered care from the perspective of patients and providers. A participatory design approach was adopted to elicit the perceptions of providers and patients with lived experiences of chronic pain and/or OUD in Jefferson County, Wisconsin. Two focus groups were conducted with each stakeholder group to identify problems that participants face with respect to chronic pain management and OUD and possible solutions. Four interviews were conducted with providers experienced in chronic pain management. Analysis of focus group sessions and interviews show consensus among patients and providers that lack of behavioral health and recovery resources create barriers to effectively manage OUD and chronic pain. However, there was discordance among the two groups about other barriers such as patient and provider attitudes, tapering approach, and access to medications for OUD. This tension among patients and providers can influence patients’ retention in therapy. More efforts are needed to mitigate stigma among providers in rural communities and support psychosocial needs of patients.

Management of chronic non-cancer pain: a framework

Aim: Since publication of the CDC 2016 Guideline, opioid-related mortality in the USA has doubled and a crisis has developed among the 15-20 million Americans with chronic, moderate-to-severe, noncancer pain. Our aim was to develop a comprehensive alternative approach to management of chronic pain. Methods: Analytic review of the clinical literature. Results: Published science provides a solid framework for the management of chronic non-cancer pain, detailed here, even as it leaves many knowledge gaps, which we fill with insights from clinical experience. Conclusion: There is a sufficient basis in science and in clinical experience to achieve adequate control of chronic pain in nearly all patients in a way that adequately balances benefits and potential harms.

Topical clonidine for neuropathic pain in adults

BACKGROUND

Clonidine is a presynaptic alpha-2-adrenergic receptor agonist that has been used for many years to treat hypertension and other conditions, including chronic pain. Adverse events associated with systemic use of the drug have limited its application. Topical use of drugs has been gaining interest since the beginning of the century, as it may limit adverse events without loss of analgesic efficacy. Topical clonidine (TC) formulations have been investigated for almost 20 years in clinical trials. This is an update of the original Cochrane Review published in Issue 8, 2015.

OBJECTIVES

The objective of this review was to assess the analgesic efficacy and safety of TC compared with placebo or other drugs in adults aged 18 years or above with chronic neuropathic pain.

SEARCH METHODS

For this update we searched the Cochrane Register of Studies Online (CRSO), MEDLINE (Ovid), and Embase (Ovid) databases, and reference lists of retrieved papers and trial registries. We also contacted experts in the field. The most recent search was performed on 27 October 2021.

SELECTION CRITERIA

We included randomised, double-blind studies of at least two weeks' duration comparing TC versus placebo or other active treatment in adults with chronic neuropathic pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened references for eligibility, extracted data, and assessed risk of bias. Any discrepancies were resolved by discussion or by consulting a third review author if necessary. Where required, we contacted trial authors to request additional information. We presented pooled estimates for dichotomous outcomes as risk ratios (RRs) with 95% confidence intervals (CIs), and continuous outcomes as mean differences (MDs) with P values. We used Review Manager Web software to perform the meta-analyses. We used a fixed-effect model if we considered heterogeneity as not important; otherwise, we used a random-effects model.  The review primary outcomes were: participant-reported pain relief of 50% or greater; participant-reported pain relief of 30% or greater; much or very much improved on Patient Global Impression of Change scale (PGIC); and very much improved on PGIC. Secondary outcomes included withdrawals due to adverse events; participants experiencing at least one adverse event; and withdrawals due to lack of efficacy. All outcomes were measured at the longest follow-up period. We assessed the certainty of evidence using GRADE and created two summary of findings tables.

MAIN RESULTS

We included four studies in the review (two new in this update), with a total of 743 participants with painful diabetic neuropathy (PDN). TC (0.1% or 0.2%) was applied in gel form to the painful area two to three times daily. The double-blind treatment phase of three studies lasted 8 weeks to 85 days and compared TC versus placebo. In the fourth study, the double-blind treatment phase lasted 12 weeks and compared TC versus topical capsaicin. We assessed the studies as at unclear or high risk of bias for most domains; all studies were at unclear risk of bias for allocation concealment and blinding of outcome assessment; one study was at high risk of bias for blinding of participants and personnel; two studies were at high risk of attrition bias; and three studies were at high risk of bias due to notable funding concerns. We judged the certainty of evidence (GRADE) to be moderate to very low, downgrading for study limitations, imprecision of results, and publication bias. TC compared to placebo There was no evidence of a difference in number of participants with participant-reported pain relief of 50% or greater during longest follow-up period (12 weeks) between groups (risk ratio (RR) 1.21, 95% confidence interval (CI) 0.78 to 1.86; 179 participants; 1 study; low certainty evidence). However, the number of participants with participant-reported pain relief of 30% or greater during longest follow-up period (8 to 12 weeks) was higher in the TC group compared with placebo (RR 1.35, 95% CI 1.03 to 1.77; 344 participants; 2 studies, very low certainty evidence). The number needed to treat for an additional beneficial outcome (NNTB) for this comparison was 8.33 (95% CI 4.3 to 50.0). Also, there was no evidence of a difference between groups for the outcomes much or very much improved on the PGIC during longest follow-up period (12 weeks) or very much improved on PGIC during the longest follow-up period (12 weeks) (RR 1.06, 95% CI 0.76 to 1.49 and RR 1.82, 95% CI 0.89 to 3.72, respectively; 179 participants; 1 study; low certainty evidence). We observed no evidence of a difference between groups in withdrawals due to adverse events and withdrawals due to lack of efficacy during the longest follow-up period (12 weeks) (RR 0.34, 95% CI 0.04 to 3.18 and RR 1.01, 95% CI 0.06 to 15.92, respectively; 179 participants; 1 study; low certainty evidence) and participants experiencing at least one adverse event during longest follow-up period (12 weeks) (RR 0.65, 95% CI 0.14 to 3.05; 344 participants; 2 studies; low certainty evidence).  TC compared to active comparator There was no evidence of a difference in the number of participants with participant-reported pain relief of 50% or greater during longest follow-up period (12 weeks) between groups (RR 1.41, 95% CI 0.99 to 2.0; 139 participants; 1 study; low certainty evidence). Other outcomes were not reported.

AUTHORS' CONCLUSIONS

This is an update of a review published in 2015, for which our conclusions remain unchanged. Topical clonidine may provide some benefit to adults with painful diabetic neuropathy; however, the evidence is very uncertain. Additional trials are needed to assess TC in other neuropathic pain conditions and to determine whether it is possible to predict who or which groups of people will benefit from TC.

Update on the role of naldemedine in opioid-induced constipation in patients with chronic noncancer pain

Chronic noncancer pain (CNCP) affects up to 20% of adults and can interfere with activities of daily living. Up to 4% of adults in the United States receive chronic opioid therapy and up to 57% of patients on long-term opioids for CNCP report opioid-induced constipation (OIC). OIC is essentially constipation occurring after starting opioid treatment. While laxatives are traditionally the first-line therapy for OIC, 81% of patients taking daily laxatives and opioids still reported OIC and considered that it negatively affected their quality of life. Naldemedine is a peripherally acting µ-opioid receptor antagonists (PAMORA) approved for the treatment of OIC in patients with CNCP. This article reviews the mechanism of action, efficacy, and safety of naldemedine in CNCP patients. Naldemedine improves OIC in patients with CNCP by acting as an opioid receptor antagonist in the gastrointestinal tract. It does not interfere with the analgesic properties of opioids or cause withdrawal symptoms since these effects are centrally mediated, and naldemedine does not cross the blood brain barrier. Naldemedine showed significant and sustained improvement in frequency of bowel movements, quality of life, and constipation-related symptoms. It is generally well tolerated with a higher incidence of gastrointestinal adverse events of mild or moderate severity such as diarrhea, abdominal pain, or vomiting compared to placebo. While there are no randomized, controlled trials that compare head-to-head pharmacological therapies used for treatment of OIC, network meta-analysis shows that naldemedine has an overall good benefit-risk profile compared to the other approved medications.

Factors Influencing Pain Management of Patients with Osteoarthritis: A Cross-Sectional Study

Background: Osteoarthritis (OA) is a complex disease associated with chronic pain. Many patients treat their joint pain at a symptomatic level with over-the-counter (OTC) pain medications, often without the knowledge of their physicians. The aim of this study was to provide physicians with data about osteoarthritic patients’ habits of pain management and to examine the explanatory factors of various ways of self-treatment. Methods: A cross-sectional study involving 189 patients with hip or knee OA and scheduled for joint replacement surgery was carried out. Participants filled out a self-administered questionnaire consisting of the Western Ontario and McMaster Universities Osteoarthritis Index and questions about their methods of alleviating pain. Results: 2.6% of patients did not use anything to alleviate their pain, while 63% practiced a non-pharmacological method. Diclofenac was the most frequently used drug, followed by ibuprofen. Profession had the greatest impact on medication habits; patients doing manual work were significantly more likely to take OTC non-steroidal anti-inflammatory drugs and use topical analgesics. Conclusions: Patients utilized a wide variety of pain management techniques. They seemed to use well-known painkillers, even if their side effects were less desirable. Such patients require comprehensive pain management, including educational and behavioural interventions, complemented by topical and oral medication.

Transcutaneous Electrical Nerve Stimulation in Rodent Models of Neuropathic Pain: A Meta-Analysis

Transcutaneous electrical nerve stimulation (TENS) is a non-invasive therapeutic intervention that is typically used for many years to treat chronic pain in patients who are refractory to pain medications. However, evidence of the efficacy of TENS treatment for neuropathic pain is lacking in humans. To further understand the efficacy of TENS under various intervention conditions and illuminate the current circumstance and future research directions, we systematically reviewed animal studies investigating the efficacy of TENS in relieving pain in neuropathic pain rodent models. We searched the Cochrane Library, EMBASE, MEDLINE (via PubMed), and Web of Science and identified 11 studies. Two meta-analyses were performed. The first meta-analysis showed that a single TENS treatment was capable of temporarily ameliorating neuropathic pain when compared to control groups with a significant effect (standardized mean difference: 1.54; 95% CI: 0.65, 2.42; p = 0.0007; I² = 58%). Significant temporary alleviation in neuropathic pain intensity was also observed in the meta-analysis of repetitive TENS (standardized mean difference: 0.85; 95% CI: 0.31, 1.40; p = 0.002; I² = 75%). Subgroup analysis showed no effect of the timing of the application of TENS (test for subgroup difference, p = 0.47). Leave-one-out sensitivity analyses suggested that no single study had an outsized effect on the pooled estimates, which may partly prove the robustness of these findings. Other stratified analyses were prevented by the insufficient number of included studies. Overall, current data suggest that TENS might be a promising therapy to ameliorate neuropathic pain. However, the high risk of bias in the included studies suggests that cautions must be considered when interpreting these findings and it is not reasonable to directly generalize the results obtained from animal studies to clinical practice. Future studies should pay more attention to improving the quality of study design and reporting, thereby facilitating the understanding of mechanisms underlying TENS treatment, reducing more potentially unsuccessful clinical trials, and optimizing the efficacy of TENS for people with neuropathic pain.

Novel Histone Modifications in Microglia Derived from a Mouse Model of Chronic Pain

As the resident immune cells in the central nervous system, microglia play an important role in the maintenance of its homeostasis. Dysregulation of microglia has been associated with the development and maintenance of chronic pain. However, the relevant molecular pathways remain poorly defined. In this study, we used a mass spectrometry-based proteomic approach to screen potential changes of histone protein modifications in microglia isolated from the brain of control and cisplatin-induced neuropathic pain adult C57BL/6J male mice. We identified several novel microglial histone modifications associated with pain including statistically significantly decreased histone H3.1 lysine 27 mono-methylation (H3.1K27me1, 54.8% of control) and lysine 56 tri-methylation (7.5% of control), as well as a trend suggesting increased histone 3 tyrosine 41 nitration. We further investigated the functional role of H3.1K27me1 and found that treatment of cultured microglial cells for 4 consecutive days with 1-10 μM of NCDM-64, a potent and selective inhibitor of lysine demethylase 7A, an enzyme responsible for the demethylation of H3K27me1, dose-dependently elevated its levels with a greater than a 2-fold increase observed at 10 μM compared to vehicle-treated control cells. Moreover, pre-treatment of mice with NCDM-64 (10 or 25 mg/kg/day, i.p.) prior to cisplatin treatment prevented the development of neuropathic pain in mice. The identification of specific chromatin marks in microglia associated with chronic pain may yield critical insight into the contribution of microglia to the development and maintenance of pain, and opens new avenues for the development of novel non-opioid therapeutics for the effective management of chronic pain. This article is protected by copyright. All rights reserved.

Molecular Mechanism of Gelsemium elegans (Gardner and Champ.) Benth. Against Neuropathic Pain Based on Network Pharmacology and Experimental Evidence

Gelsemium elegans (Gardner and Champ.) Benth. (Gelsemiaceae) (GEB) is a toxic plant indigenous to Southeast Asia especially China, and has long been used as Chinese folk medicine for the treatment of various types of pain, including neuropathic pain (NPP). Nevertheless, limited data are available on the understanding of the interactions between ingredients-targets-pathways. The present study integrated network pharmacology and experimental evidence to decipher molecular mechanisms of GEB against NPP. The candidate ingredients of GEB were collected from the published literature and online databases. Potentially active targets of GEB were predicted using the SwissTargetPrediction database. NPP-associated targets were retrieved from GeneCards, Therapeutic Target database, and DrugBank. Then the protein-protein interaction network was constructed. The DAVID database was applied to Gene Ontology and Kyoto Encyclopedia of Genes and Genome pathway enrichment analysis. Molecular docking was employed to validate the interaction between ingredients and targets. Subsequently, a 50 ns molecular dynamics simulation was performed to analyze the conformational stability of the protein-ligand complex. Furthermore, the potential anti-NPP mechanisms of GEB were evaluated in the rat chronic constriction injury model. A total of 47 alkaloids and 52 core targets were successfully identified for GEB in the treatment of NPP. Functional enrichment analysis showed that GEB was mainly involved in phosphorylation reactions and nitric oxide synthesis processes. It also participated in 73 pathways in the pathogenesis of NPP, including the neuroactive ligand-receptor interaction signaling pathway, calcium signaling pathway, and MAPK signaling pathway. Interestingly, 11-Hydroxyrankinidin well matched the active pockets of crucial targets, such as EGFR, JAK1, and AKT1. The 11-hydroxyrankinidin-EGFR complex was stable throughout the entire molecular dynamics simulation. Besides, the expression of EGFR and JAK1 could be regulated by koumine to achieve the anti-NPP action. These findings revealed the complex network relationship of GEB in the "multi-ingredient, multi-target, multi-pathway" mode, and explained the synergistic regulatory effect of each complex ingredient of GEB based on the holistic view of traditional Chinese medicine. The present study would provide a scientific approach and strategy for further studies of GEB in the treatment of NPP in the future.

Wearable transcutaneous electrical nerve stimulation (actiTENS®) is effective and safe for the treatment of knee osteoarthritis pain: a randomized controlled trial versus weak opioids

INTRODUCTION

Despite their poor tolerance, especially in the elderly, weak opioids (WO) remain commonly prescribed for patients with knee osteoarthritis (KOA). We compared the efficacy and safety of a new wearable transcutaneous electrical nerve stimulation (W-TENS) device with WO for the treatment of moderate-to-severe, nociceptive KOA chronic pain.

METHODS

The study was a non-inferiority, multicentric, prospective, randomized, single-blind, controlled, 2-parallel groups Trial. A total of 110 patients with KOA were included (Kellgren-Lawrence radiographic grade ⩾2; American College of Rheumatology criteria), with chronic moderate-to-severe nociceptive pain (mean 8-day pain intensity (PI) ⩾ 4 on an 11-point numerical rating scale), in failure to non-opioid analgesics, including nonsteroidal anti-inflammatory drugs (NSAIDs). Patients with neuropathic pain were excluded. The co-primary endpoints were mean PI at 3 months (M3) and number of potentially treatment-related adverse events (TRAEs). Secondary outcomes included Western Ontario MAC Master University function subscale (range, 0-68), additional pain and quality of life measures, and responder rates.

RESULTS

The non-inferiority of W-TENS was demonstrated in both the per protocol (PP) and intent-to-treat (ITT) populations. At M3, PI in PP population was 3.87 (2.12) compared with 4.66 (2.37) [delta: -0.79 (0.44); 95% CI (-1.65, 0.08)] in W-TENS and WO groups, respectively. A planned superiority analysis showed a significant superiority of W-TENS over WO on PI at M3 (p = 0.0124). The number of TRAEs was significantly lower in the W-TENS group (n = 7) than in the WO group (n = 36) (p < 0.001). Other secondary outcomes also favored W-TENS.

CONCLUSION

W-TENS was more effective and better tolerated than WO in the treatment of chronic nociceptive KOA pain and offers an interesting non-pharmacological analgesic alternative in the management of KOA.Trial Registration: ClinicalTrials.gov: NCT03902340.

Implanted spinal neuromodulation interventions for chronic pain in adults

BACKGROUND

Implanted spinal neuromodulation (SNMD) techniques are used in the treatment of refractory chronic pain. They involve the implantation of electrodes around the spinal cord (spinal cord stimulation (SCS)) or dorsal root ganglion (dorsal root ganglion stimulation (DRGS)), and a pulse generator unit under the skin. Electrical stimulation is then used with the aim of reducing pain intensity.

OBJECTIVES

To evaluate the efficacy, effectiveness, adverse events, and cost-effectiveness of implanted spinal neuromodulation interventions for people with chronic pain.

SEARCH METHODS

We searched CENTRAL, MEDLINE Ovid, Embase Ovid, Web of Science (ISI), Health Technology Assessments, ClinicalTrials.gov and World Health Organization International Clinical Trials Registry from inception to September 2021 without language restrictions, searched the reference lists of included studies and contacted experts in the field.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing SNMD interventions with placebo (sham) stimulation, no treatment or usual care; or comparing SNMD interventions + another treatment versus that treatment alone. We included participants ≥ 18 years old with non-cancer and non-ischaemic pain of longer than three months duration. Primary outcomes were pain intensity and adverse events. Secondary outcomes were disability, analgesic medication use, health-related quality of life (HRQoL) and health economic outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened database searches to determine inclusion, extracted data and evaluated risk of bias for prespecified results using the Risk of Bias 2.0 tool. Outcomes were evaluated at short- (≤ one month), medium- four to eight months) and long-term (≥12 months). Where possible we conducted meta-analyses. We used the GRADE system to assess the certainty of evidence.

MAIN RESULTS

We included 15 unique published studies that randomised 908 participants, and 20 unique ongoing studies. All studies evaluated SCS. We found no eligible published studies of DRGS and no studies comparing SCS with no treatment or usual care. We rated all results evaluated as being at high risk of bias overall. For all comparisons and outcomes where we found evidence, we graded the certainty of the evidence as low or very low, downgraded due to limitations of studies, imprecision and in some cases, inconsistency. Active stimulation versus placebo SCS versus placebo (sham) Results were only available at short-term follow-up for this comparison. Pain intensity Six studies (N = 164) demonstrated a small effect in favour of SCS at short-term follow-up (0 to 100 scale, higher scores = worse pain, mean difference (MD) -8.73, 95% confidence interval (CI) -15.67 to -1.78, very low certainty). The point estimate falls below our predetermined threshold for a clinically important effect (≥10 points). No studies reported the proportion of participants experiencing 30% or 50% pain relief for this comparison. Adverse events (AEs) The quality and inconsistency of adverse event reporting in these studies precluded formal analysis. Active stimulation + other intervention versus other intervention alone SCS + other intervention versus other intervention alone (open-label studies) Pain intensity Mean difference Three studies (N = 303) demonstrated a potentially clinically important mean difference in favour of SCS of -37.41 at short term (95% CI -46.39 to -28.42, very low certainty), and medium-term follow-up (5 studies, 635 participants, MD -31.22 95% CI -47.34 to -15.10 low-certainty), and no clear evidence for an effect of SCS at long-term follow-up (1 study, 44 participants, MD -7 (95% CI -24.76 to 10.76, very low-certainty). Proportion of participants reporting ≥50% pain relief We found an effect in favour of SCS at short-term (2 studies, N = 249, RR 15.90, 95% CI 6.70 to 37.74, I2 0% ; risk difference (RD) 0.65 (95% CI 0.57 to 0.74, very low certainty), medium term (5 studies, N = 597, RR 7.08, 95 %CI 3.40 to 14.71, I2 = 43%; RD 0.43, 95% CI 0.14 to 0.73, low-certainty evidence), and long term (1 study, N = 87, RR 15.15, 95% CI 2.11 to 108.91 ; RD 0.35, 95% CI 0.2 to 0.49, very low certainty) follow-up. Adverse events (AEs) Device related No studies specifically reported  device-related adverse events at short-term follow-up. At medium-term follow-up, the incidence of lead failure/displacement (3 studies N = 330) ranged from 0.9 to 14% (RD 0.04, 95% CI -0.04 to 0.11, I2 64%, very low certainty). The incidence of infection (4 studies, N = 548) ranged from 3 to 7% (RD 0.04, 95%CI 0.01, 0.07, I2 0%, very low certainty). The incidence of reoperation/reimplantation (4 studies, N =5 48) ranged from 2% to 31% (RD 0.11, 95% CI 0.02 to 0.21, I2 86%, very low certainty). One study (N = 44) reported a 55% incidence of lead failure/displacement (RD 0.55, 95% CI 0.35, 0 to 75, very low certainty), and a 94% incidence of reoperation/reimplantation (RD 0.94, 95% CI 0.80 to 1.07, very low certainty) at five-year follow-up. No studies provided data on infection rates at long-term follow-up. We found reports of some serious adverse events as a result of the intervention. These included autonomic neuropathy, prolonged hospitalisation, prolonged monoparesis, pulmonary oedema, wound infection, device extrusion and one death resulting from subdural haematoma. Other No studies reported the incidence of other adverse events at short-term follow-up. We found no clear evidence of a difference in otherAEs at medium-term (2 studies, N = 278, RD -0.05, 95% CI -0.16 to 0.06, I2 0%) or long term (1 study, N = 100, RD -0.17, 95% CI -0.37 to 0.02) follow-up. Very limited evidence suggested that SCS increases healthcare costs. It was not clear whether SCS was cost-effective.

AUTHORS' CONCLUSIONS

We found very low-certainty evidence that SCS may not provide clinically important benefits on pain intensity compared to placebo stimulation. We found low- to very low-certainty evidence that SNMD interventions may provide clinically important benefits for pain intensity when added to conventional medical management or physical therapy. SCS is associated with complications including infection, electrode lead failure/migration and a need for reoperation/re-implantation. The level of certainty regarding the size of those risks is very low. SNMD may lead to serious adverse events, including death. We found no evidence to support or refute the use of DRGS for chronic pain.

Prediction of chronic postsurgical pain in adults: a protocol for multivariable prediction model development

Introduction

Chronic postsurgical pain (CPSP) is a condition that affects an estimated 10%–50% of adults, depending on the surgical procedure. CPSP often interferes with activities of daily living and may have a negative impact on quality of life, emotional and physical well-being. Clinical prediction models can help clinicians target preventive strategies towards patients at high-risk of CPSP. Therefore, the objective of this study is to develop a clinically applicable and generalisable prediction model for CPSP in adults.

Methods and analysis

This research will be a prospective single-centre observational cohort study in Denmark spanning approximately 1 year or until a predefined number of patients are recruited (n=1526). Adult patients aged 18 years and older scheduled to undergo surgery will be recruited at Aarhus University Hospital. The primary outcome is CPSP 3 months after surgery defined as average pain intensity at rest or on movement ≥3 on numerical rating scale (NRS) within the past week, and/or average pain interference ≥3 on NRS among any of seven short-form Brief Pain Inventory items in the past week (general activity, mood, walking ability, normal work (including housework), relations with other people, sleep and enjoyment of life). Logistic regression will be used to conduct multivariate analysis. Predictive model performance will be evaluated by discrimination, calibration and model classification.

Ethics and dissemination

This research has been approved by Central Region Denmark and will be conducted in accordance with the Danish Data Protection Act and Declaration of Helsinki. Study findings will be disseminated through conference presentations and peer-reviewed publication. A CPSP risk calculator (CPSP-RC) will be developed based on predictors retained in the final models. The CPSP-RC will be made available online and as a mobile application to be easily accessible for clinical use and future research including validation and clinical impact assessments.

Trial registration number

NCT04866147.

Gender differences in perceived pain and health-related quality of life in people with chronic non-malignant pain: a cross-sectional study

BACKGROUND

Chronic pain has a disproportionate impact on members of vulnerable population groups, and women are at substantially greater risk than men of suffering multiple chronic pain disorders. Moreover, one of the aspects most affected by the presence of chronic pain is that of health-related quality of life (HRQoL), worsening over time, as the disease persists.

OBJECTIVES

To describe the profile of patients who suffer non-malignant chronic pain, from a gender perspective, and to identify factors related to their HRQoL and mental health.

DESIGN

A cross-sectional study was carried out in patients with chronic non-cancer pain.

METHODS

Sociodemographic variables, pain intensity at rest and in motion, SF-36 health questionnaire, anxiety, and depression were evaluated.

RESULTS

The study population consisted of 531 subjects, of whom 64.2% were women. The mean age was 52.9 (SD: 10.4) years. The pain intensity recorded on the visual analogue scale was 6 (SD: 2.7) at rest and 8 (SD: 2) in motion. Physical component score and mental component score of quality of life were worse in women vs men: 33.73 (6.77) vs 32.33 (6.20), for the physical component; 36.89 (12.77) vs 32.91 (11.51), for mental component. Anxiety, depression and pain intensity, showed poorer results in women.

CONCLUSION

Gender is a factor that should be considered in assessing and managing chronic pain, due to its influence on the perception of pain, and HRQoL.

IMPACT STATEMENT

Gender is an important modifier of the perception of pain, and HRQoL. To achieve a patient-centred approach, nurses should incorporate gender as a differential factor to adapt and individualize pain management and patient education.

Prognostic prediction models for chronic postsurgical pain in adults: a systematic review

ABSTRACT

Chronic postsurgical pain (CPSP) affects an estimated 10% to 50% of adults depending on the type of surgical procedure. Clinical prediction models can help clinicians target preventive strategies towards patients at high risk for CPSP. Therefore, the objective of this systematic review was to identify and describe existing prediction models for CPSP in adults. A systematic search was performed in MEDLINE, Embase, PsychINFO, and the Cochrane Database of Systematic Reviews in March 2020 for English peer-reviewed studies that used data collected between 2000 and 2020. Studies that developed, validated, or updated a prediction model in adult patients who underwent any surgical procedure were included. Two reviewers independently screened titles, abstracts, and full texts for eligibility; extracted data; and assessed risk of bias using the Prediction model Risk of Bias Assessment Tool. The search identified 2037 records; 28 articles were reviewed in full text. Fifteen studies reporting on 19 prediction models were included; all were at high risk of bias. Model discrimination, measured by the area under receiver operating curves or c-statistic, ranged from 0.690 to 0.816. The most common predictors identified in final prediction models included preoperative pain in the surgical area, preoperative pain in other areas, age, sex or gender, and acute postsurgical pain. Clinical prediction models may support prevention and management of CPSP, but existing models are at high risk of bias that affects their reliability to inform practice and generalizability to wider populations. Adherence to standardized guidelines for clinical prediction model development is necessary to derive a prediction model of value to clinicians.

Self-perceived competence of dental students regarding the management of orofacial pain: a cross-sectional study

BACKGROUND

There is limited data on Pakistani dental students perceived competence in managing orofacial pain (OFP). This study aims to evaluate dental students self-perceived competence regarding the management of orofacial pain.

METHODS

This cross-sectional study was conducted in Karachi at randomly selected two public and four private dental schools. This survey was conducted online from November 2020 to December 2020 in six dental schools. A questionnaire link was sent to the 475 students. A chi-square test and independent-sample t-test were conducted to assess the frequency distribution and compare mean scores of knowledge, diagnosis, and management parameters.

RESULTS

Of the 475 students, 280 students filled the online survey leaving a response rate of 59%. A significant number of fourth-year students, 65 (51%, p = 0.005), feels knowledgeable regarding neuropathic pain compared to third-year students. The majority of the fourth-year students, 100 (78%, p = 0.010), feel comfortable managing intraoral pain. Almost all the students reported thinking that they need more knowledge related to five types of OFP. The fourth-year students had high mean scores related to knowledge, comfort in diagnosing and managing OFP categories.

CONCLUSION

This study found that dental students perceived competence regarding orofacial pain management varies in relation to specific categories, being lowest for psychogenic pain.

Cannabis against chronic musculoskeletal pain: a scoping review on users and their perceptions

Background

Chronic musculoskeletal pain (CMP) may lead to reduced physical function and is the most common cause of chronic non-cancer pain. Currently, the pharmacotherapeutic options against CMP are limited and frequently consist of pain management with non-steroidal anti-inflammatories, gabapentinoids, or opioids, which carry major adverse effects. Although the effectiveness of medical cannabis (MC) for CMP still lacks solid evidence, several patients suffering from it are exploring this therapeutic option with their physicians.

Objectives

Little is known about patients’ perceptions of their MC treatment for CMP. We aimed to increase this knowledge, useful for healthcare professionals and patients considering this treatment, by conducting a scoping literature review, following guidance by Arksey and O’Malley, to describe the views and perceptions of adult patients who had consumed MC to relieve chronic CMP.

Methods

Databases (PUBMED, EMBASE, Web of Science) and websites were searched using combinations of controlled and free vocabulary. All studies and study designs reporting on patients’ perceptions regarding MC against CMP were considered. Studies had to include adult patients reporting qualitatively or quantitatively, i.e., through questionnaires, on MC use to treat CMP or other non-cancer pain, since studies reporting exclusively on perceptions regarding CMP were very rare. Study characteristics were extracted and limitations of the study quality were assessed. The review includes patients’ demographic characteristics, patterns of MC use, perceived positive and negative effects, use of alcohol or other drugs, reported barriers to CM use, and funding sources of the studies.

Results

Participants of the 49 included studies reported that MC use helped them to reduce CMP and other chronic non-cancer pain, with only minor adverse effects, and some reported improved psychological well-being.

In the included studies, men represent between 18 and 88% of the subjects. The mean age of participants in these studies (42/49) varied between 28.4 and 62.8 years old. The most common route of administration is inhalation.

Conclusion

MC users suffering from CMP or other chronic non-cancer pain perceived more benefits than harms. However, the information from these studies has several methodological limitations and results are exploratory. These user-reported experiences must thus be examined by well-designed and methodologically sound clinical or observational studies, particularly regarding CMP, where reports are very scarce.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42238-021-00096-8.

Association between malnutrition risk and pain in older hospital patients

OBJECTIVE

To describe the prevalence of malnutrition risk and pain in older hospital patients and characterise the association between these two problems.

RESEARCH METHODS AND PROCEDURES

The study includes a secondary data analysis of data collected in two cross-sectional studies. Data collection was performed in 2017 and 2018 using a standardised and tested questionnaire. The study protocol was approved by an ethical committee.

RESULTS

Data from 3406 patients were analysed. Among the participants, 24.6% of the patients were at risk of malnutrition, and 59.6% of the patients reported feeling pain. A significantly higher number of patients with pain (26.4%) were at risk of malnutrition than patients without pain (22.1%). The multivariate logistic regression analysis showed that patients with severe/very severe or unbearable pain were 1.439 times more likely to develop a risk of malnutrition than patients without pain. Patients with cancer or diseases of the digestive system were twice as likely to develop malnutrition than those without these diseases.

CONCLUSIONS

The results of this study show that older patients with severe pain are at higher risk of developing a risk of malnutrition than those without pain, although the study design (cross-sectional) does not imply causality. Therefore, special efforts should be made to assess pain in these patients to reduce the negative consequences of this pain, such as malnutrition.

Virtual reality or isokinetic training; its effect on pain, kinesiophobia and serum stress hormones in chronic low back pain: A randomized controlled trial

BACKGROUND

Evidence on the latest technologies in rehabilitation for reducing pain and altering serum stress hormones in low back pain (LBP) was lacking.

OBJECTIVE

To find the clinical and hormonal effects of virtual reality training (VRT) and isokinetic training (IKT) in chronic LBP patients.

METHODS

Through the simple random sampling method, 60 university football players with chronic LBP were allocated into three groups: NVRT= 20, NIKT= 20 and NCONTROL= 20. The three groups underwent different exercises for 4 weeks. Clinical (pain intensity and kinesiophobia) and hormonal (glucose, insulin, HOMA-IR, growth hormone, prolactin, ACTH and cortisol) values were measured at baseline, after 4 weeks and 6 months.

RESULTS

Four weeks following training, the VRT and IKT groups showed significant changes in pain intensity and kinesiophobia in comparison to the control group (p< 0.05). Hormonal measures also showed significant improvement in the VRT group in comparison to the other two groups (p< 0.05).

CONCLUSION

Training through virtual reality and isokinetic exercise is an effective approach in terms of pain and kinesiophobia. In terms of hormonal analysis, virtual reality shows slightly more improvements than isokinetic training in subjects with chronic LBP.