As if one pain problem was not enough: prevalence and patterns of coexisting chronic pain conditions and their impact on treatment outcomes

The Combined Relationship of Prescription Drug Monitoring Program Enactment and Medical Cannabis Laws with Chronic Pain-Related Healthcare Visits

BACKGROUND

U.S. state electronic prescription drug monitoring programs (PDMPs) are associated with reduced opioid dispensing among people with chronic pain and may impact use of other chronic pain treatments. In states with medical cannabis laws (MCLs), patients can use cannabis for chronic pain management, reducing their need for chronic-pain related treatment visits and moderating effects of PDMP laws.

OBJECTIVE

Given high rates of chronic pain among Medicaid enrollees, we examined associations between PDMP enactment in the presence or absence of MCL on chronic pain-related outpatient and emergency department (ED) visits.

DESIGN

We created annual cohorts of Medicaid enrollees with chronic pain diagnoses using national Medicaid claims data from 2002-2013 and 2016. Negative binomial hurdle models produced adjusted odds ratios (aOR) for the likelihood of any chronic pain-related outpatient or ED visit and incident rate ratios (IRR) for the rate of visits among patients with ≥ 1 visit.

PARTICIPANTS

Medicaid enrollees aged 18-64 years with chronic pain (N = 4,878,462).

MAIN MEASURES

A 3-level state-year variable with the following categories: 1) no PDMP, 2) PDMP enactment in the absence of MCL, or 3) PDMP enactment in the presence of MCL. Healthcare codes for chronic pain-related outpatient and ED visits each year.

KEY RESULTS

The sample was primarily female (67.2%), non-Hispanic White (51.2%), and ages 40-55 years (37.2%). Compared to no-PDMP states, PDMP enactment in the absence of MCL was not associated with chronic pain-related outpatient visits but PDMP enactment in the presence of MCL was associated with lower odds of chronic pain-related outpatient visits (aOR = 0.81, 95% CI:0.71-0.92). PDMP enactment was not associated with ED visits, irrespective of MCL.

CONCLUSIONS

During a period of PDMP and MCL expansion, our findings suggest treatment shifts for persons with chronic pain away from outpatient settings, potentially related to increased use of cannabis for chronic pain management.

Presence of endometriosis and chronic overlapping pain conditions negatively impacts the pain experience in women with chronic pelvic-abdominal pain: A cross-sectional survey

BACKGROUND

Evidence of overlap between endometriosis and chronic pain conditions is emerging; however, little is known about how the pain experience differs based on the presence or absence of endometriosis.

OBJECTIVES

In a sample of women reporting chronic pelvic-abdominal pain (CPP), the aim of this study was to characterize differences in pain symptomatology between women with and without endometriosis and to examine the influence of chronic overlapping pain conditions (COPCs) on pain among these two groups.

DESIGN

This was a cross-sectional study, based on an online survey.

METHODS

Participants (aged 18+ years) completed a survey collecting pain diagnoses and symptoms assessing pelvic pain severity, pain interference, and pain impact. Independent sample t-tests, chi-square, and multiple linear regression models were employed to analyze group differences in pain symptomatology and COPCs.

RESULTS

Of the 525 respondents with CPP, 25% (n = 133) reported having endometriosis. Women with endometriosis were younger at the onset of pelvic pain, relative to women without endometriosis (p = 0.04). There were no differences in age, race, ethnicity, or duration of pelvic pain between women with and without endometriosis. Women with endometriosis reported higher pelvic pain severity (+0.8, 95% CI = 0.4-1.1), pain interference (+5.9, 95% CI = 2.4-9.3), and pain impact (+1.9, 95% CI = 0.8-2.9). Endometriosis was associated with a higher number of COPCs (p = 0.003), with 25% (n = 33) of women reporting ⩾3 overlapping pain conditions compared with 12% (n = 45) of those without endometriosis. Women with endometriosis had a higher frequency of fibromyalgia (p < 0.001), chronic fatigue syndrome (p < 0.001), and temporomandibular disorder (p = 0.001). The number of COPCs was associated with higher pain severity, interference, and impact, independently of endometriosis.

CONCLUSION

Women with endometriosis experienced higher levels of pain-related burden and COPCs compared with those without endometriosis. Pain intensity, interference, and impact increased with a higher number of pain conditions regardless of endometriosis presence.

"I could not bear it": Perceptions of chronic pain among Somali pastoralists in Ethiopia. A qualitative study

BACKGROUND

Pain is a major public health problem in the Global South, particularly among marginalized communities, such as Somali pastoralists. Yet, the topic of chronic pain has not yet been comprehensively studied in Sub-Saharan Africa, specifically in the Somali region of Ethiopia. Therefore, this study aims to explore the perceptions and notions of chronic pain among Somali pastoralists in this context.

METHODS

This study used an explorative qualitative design. We performed semi-structured, face-to-face interviews with 20 purposively selected female and male Somali pastoralists with chronic pain. For data analysis, we applied the Framework Method by Gale et al. and explained patterns drawing on the Enactive Approach to Pain proposed by Stilwell and Harman.

FINDINGS

Six different themes emerged: (1) "Pain as a symptom of harsh daily life", (2) "Pain descriptions and dimensions", (3) "Temporality of pain", (4) "Pain-related stigma and stoicism" (5) "Mediating role of spirituality", and (6) "Impact of pain on daily life activities".

CONCLUSIONS

Somali pastoralists described their chronic pain as a multicausal and relational experience. Pastoralists (especially women) commonly refrained from communicating their pain and represented aspects of social stigma and stoicism. The mediating role of spirituality aided pastoralists to make sense of their pain and to ease its impact on their harsh daily life. The findings of this study can contribute to raise awareness of chronic pain issues among pastoralists. They highlight the need for policymakers to prioritize the improvement of pastoralist-specific pain management. Necessary resources and skills should be available within health care facilities. Pain management should be accessible, affordable and culturally acceptable for this population.

Mental and Physical Health Conditions Among U.S. Veterans with Cannabis Use and Cannabis Use Disorders

Purpose of Review

Veterans are a large population that is disproportionately affected by various physical and mental health conditions. The primary aim of this review is to provide a concise overview of recent literature on the prevalence of cannabis use and cannabis use disorder (CUD) among US Veterans, and associations with mental and physical health conditions. We also addressed gaps in the literature by investigating associations between CUD and mental and physical health conditions in 2019 data from the Veterans Health Administration (VHA; N=5,657,277).

Recent Findings

In total, 25 studies were reviewed. In 2019, the prevalence of Veteran cannabis use ranged from 11.9%-18.7%. Cannabis use and CUD were associated with bipolar disorders, psychotic disorders, suicidality, pain conditions, and other substance use, but less consistently associated with depressive disorders, anxiety disorders, and posttraumatic stress disorder. Analyses of 2019 VHA data indicated that CUD was strongly associated with a broad array of physical and mental health conditions and mortality.

Summary

Cannabis use and CUD are prevalent and highly comorbid with other conditions among US Veterans. Harm reduction methods tailored to these populations are needed.

Chronic Pain, Cannabis Legalization and Cannabis Use Disorder in Veterans Health Administration Patients, 2005 to 2019

Background

The risk for cannabis use disorder (CUD) is elevated among U.S. adults with chronic pain, and CUD rates are disproportionately increasing in this group. Little is known about the role of medical cannabis laws (MCL) and recreational cannabis laws (RCL) in these increases. Among U.S. Veterans Health Administration (VHA) patients, we examined whether MCL and RCL effects on CUD prevalence differed between patients with and without chronic pain.

Methods

Patients with ≥1 primary care, emergency, or mental health visit to the VHA and no hospice/palliative care within a given calendar year, 2005-2019 (yearly n=3,234,382 to 4,579,994) were analyzed using VHA electronic health record (EHR) data. To estimate the role of MCL and RCL enactment in the increases in prevalence of diagnosed CUD and whether this differed between patients with and without chronic pain, staggered-adoption difference-in-difference analyses were used, fitting a linear binomial regression model with fixed effects for state, categorical year, time-varying cannabis law status, state-level sociodemographic covariates, a chronic pain indicator, and patient covariates (age group [18-34, 35-64; 65-75], sex, and race and ethnicity). Pain was categorized using an American Pain Society taxonomy of painful medical conditions.

Outcomes

In patients with chronic pain, enacting MCL led to a 0·14% (95% CI=0·12%-0·15%) absolute increase in CUD prevalence, with 8·4% of the total increase in CUD prevalence in MCL-enacting states attributable to MCL. Enacting RCL led to a 0·19% (95%CI: 0·16%, 0·22%) absolute increase in CUD prevalence, with 11·5% of the total increase in CUD prevalence in RCL-enacting states attributable to RCL. In patients without chronic pain, enacting MCL and RCL led to smaller absolute increases in CUD prevalence (MCL: 0·037% [95%CI: 0·03, 0·05]; RCL: 0·042% [95%CI: 0·02, 0·06]), with 5·7% and 6·0% of the increases in CUD prevalence attributable to MCL and RCL. Overall, MCL and RCL effects were significantly greater in patients with than without chronic pain. By age, MCL and RCL effects were negligible in patients age 18-34 with and without pain. In patients age 35-64 with and without pain, MCL and RCL effects were significant (p<0.001) but small. In patients age 65-75 with pain, absolute increases were 0·10% in MCL-only states and 0·22% in MCL/RCL states, with 9·3% of the increase in CUD prevalence in MCL-only states attributable to MCL, and 19.4% of the increase in RCL states attributable to RCL. In patients age 35-64 and 65-75, MCL and RCL effects were significantly greater in patients with pain.

Interpretation

In patients age 35-75, the role of MCL and RCL in the increasing prevalence of CUD was greater in patients with chronic pain than in those without chronic pain, with particularly pronounced effects in patients with chronic pain age 65-75. Although the VHA offers extensive behavioral and non-opioid pharmaceutical treatments for pain, cannabis may seem a more appealing option given media enthusiasm about cannabis, cannabis commercialization activities, and widespread public beliefs about cannabis efficacy. Cannabis does not have the risk/mortality profile of opioids, but CUD is a clinical condition with considerable impairment and comorbidity. Because cannabis legalization in the U.S. is likely to further increase, increasing CUD prevalence among patients with chronic pain following state legalization is a public health concern. The risk of chronic pain increases as individuals age, and the average age of VHA patients and the U.S. general population is increasing. Therefore, clinical monitoring of cannabis use and discussion of the risk of CUD among patients with chronic pain is warranted, especially among older patients.

Research in Context

Evidence before this study: Only three studies have examined the role of state medical cannabis laws (MCL) and/or recreational cannabis laws (RCL) in the increasing prevalence of cannabis use disorder (CUD) in U.S. adults, finding significant MCL and RCL effects but with modest effect sizes. Effects of MCL and RCL may vary across important subgroups of the population, including individuals with chronic pain. PubMed was searched by DH for publications on U.S. time trends in cannabis legalization, cannabis use disorders (CUD) and pain from database inception until March 15, 2023, without language restrictions. The following search terms were used: (medical cannabis laws) AND (pain) AND (cannabis use disorder); (recreational cannabis laws) AND (pain) AND (cannabis use disorder); (cannabis laws) AND (pain) AND (cannabis use disorder). Only one study was found that had CUD as an outcome, and this study used cross-sectional data from a single year, which cannot be used to determine trends over time. Therefore, evidence has been lacking on whether the role of state medical and recreational cannabis legalization in the increasing US adult prevalence of CUD differed by chronic pain status.Added value of this study: To our knowledge, this is the first study to examine whether the effects of state MCL and RCL on the nationally increasing U.S. rates of adult cannabis use disorder differ by whether individuals experience chronic pain or not. Using electronic medical record data from patients in the Veterans Health Administration (VHA) that included extensive information on medical conditions associated with chronic pain, the study showed that the effects of MCL and RCL on the prevalence of CUD were stronger among individuals with chronic pain age 35-64 and 65-75, an effect that was particularly pronounced in older patients ages 65-75.Implications of all the available evidence: MCL and RCL are likely to influence the prevalence of CUD through commercialization that increases availability and portrays cannabis use as 'normal' and safe, thereby decreasing perception of cannabis risk. In patients with pain, the overall U.S. decline in prescribed opioids may also have contributed to MCL and RCL effects, leading to substitution of cannabis use that expanded the pool of individuals vulnerable to CUD. The VHA offers extensive non-opioid pain programs. However, positive media reports on cannabis, positive online "information" that can sometimes be misleading, and increasing popular beliefs that cannabis is a useful prevention and treatment agent may make cannabis seem preferable to the evidence-based treatments that the VHA offers, and also as an easily accessible option among those not connected to a healthcare system, who may face more barriers than VHA patients in accessing non-opioid pain management. When developing cannabis legislation, unintended consequences should be considered, including increased risk of CUD in large vulnerable subgroups of the population.

A prognostic risk score for development and spread of chronic pain

Chronic pain is a complex condition influenced by a combination of biological, psychological and social factors. Using data from the UK Biobank (n = 493,211), we showed that pain spreads from proximal to distal sites and developed a biopsychosocial model that predicted the number of coexisting pain sites. This data-driven model was used to identify a risk score that classified various chronic pain conditions (area under the curve (AUC) 0.70-0.88) and pain-related medical conditions (AUC 0.67-0.86). In longitudinal analyses, the risk score predicted the development of widespread chronic pain, the spreading of chronic pain across body sites and high-impact pain about 9 years later (AUC 0.68-0.78). Key risk factors included sleeplessness, feeling 'fed-up', tiredness, stressful life events and a body mass index >30. A simplified version of this score, named the risk of pain spreading, obtained similar predictive performance based on six simple questions with binarized answers. The risk of pain spreading was then validated in the Northern Finland Birth Cohort (n = 5,525) and the PREVENT-AD cohort (n = 178), obtaining comparable predictive performance. Our findings show that chronic pain conditions can be predicted from a common set of biopsychosocial factors, which can aid in tailoring research protocols, optimizing patient randomization in clinical trials and improving pain management.

Characterization of Fragile X Mental Retardation Protein expression in human nociceptors and their axonal projections to the spinal dorsal horn

Fragile X Mental Retardation Protein (FMRP) regulates activity-dependent RNA localization and local translation to modulate synaptic plasticity throughout the central nervous system. Mutations in the FMR1 gene that hinder or ablate FMRP function cause Fragile X Syndrome (FXS), a disorder associated with sensory processing dysfunction. FXS premutations are associated with increased FMRP expression and neurological impairments including sex dimorphic presentations of chronic pain. In mice, FMRP ablation causes dysregulated dorsal root ganglion (DRG) neuron excitability and synaptic vesicle exocytosis, spinal circuit activity, and decreased translation-dependent nociceptive sensitization. Activity-dependent, local translation is a key mechanism for enhancing primary nociceptor excitability that promotes pain in animals and humans. These works indicate that FMRP likely regulates nociception and pain at the level of the primary nociceptor or spinal cord. Therefore, we sought to better understand FMRP expression in the human DRG and spinal cord using immunostaining in organ donor tissues. We find that FMRP is highly expressed in DRG and spinal neuron subsets with substantia gelatinosa exhibiting the most abundant immunoreactivity in spinal synaptic fields. Here, it is expressed in nociceptor axons. FMRP puncta colocalized with Nav1.7 and TRPV1 receptor signals suggesting a pool of axoplasmic FMRP localizes to plasma membrane-associated loci in these branches. Interestingly, FMRP puncta exhibited notable colocalization with calcitonin gene-related peptide (CGRP) immunoreactivity selectively in female spinal cord. Our results support a regulatory role for FMRP in human nociceptor axons of the dorsal horn and implicate it in the sex dimorphic actions of CGRP signaling in nociceptive sensitization and chronic pain.

Chronic overlapping pain conditions and long-term opioid treatment

OBJECTIVES

One in 5 people in the United States lives with chronic pain. Many patients with chronic pain experience a subset of specific co-occurring pain conditions that may share a common pain mechanism and that have been designated as chronic overlapping pain conditions (COPCs). Little is known about chronic opioid prescribing patterns among patients with COPCs in primary care settings, especially among socioeconomically vulnerable patients. This study aims to evaluate opioid prescribing among patients with COPCs in US community health centers and to identify individual COPCs and their combinations that are associated with long-term opioid treatment (LOT).

STUDY DESIGN

Retrospective cohort study.

METHODS

We conducted analyses of more than 1 million patients 18 years and older based on electronic health record data from 449 US community health centers across 17 states between January 1, 2009, and December 31, 2018. Logistic regression models were used to assess the relationship between COPCs and LOT.

RESULTS

Individuals with COPCs were prescribed LOT 4 times more often than individuals without a COPC (16.9% vs 4.0%). The presence of chronic low back pain, migraine headache, fibromyalgia, or irritable bowel syndrome combined with any of the other COPCs increased the odds of LOT prescribing compared with the presence of a single COPC.

CONCLUSIONS

Although LOT prescribing has declined over time, it remains relatively high among patients with certain COPCs and for those with multiple COPCs. These study findings suggest target populations for future interventions to manage chronic pain among socioeconomically vulnerable patients.

Elevated dementia risk, cognitive decline, and hippocampal atrophy in multisite chronic pain

Numerous studies have investigated the impacts of common types of chronic pain (CP) on patients' cognitive function and observed that CP was associated with later dementia. More recently, there is a growing recognition that CP conditions frequently coexist at multiple body sites and may bring more burdens on patients' overall health. However, whether and how multisite CP (MCP) contributes to an increased risk of dementia, compared to single-site CP (SCP) and pain-free (PF), is largely unclear. In the current study, utilizing the UK Biobank cohort, we first investigated dementia risk in individuals (n = 354,943) with different numbers of coexisting CP sites using Cox proportional hazards regression models. We then applied generalized additive models to investigate whether MCP leads to excessive deterioration of participants' (n = 19,116) cognition and brain structure. We found that individuals with MCP were associated with significantly higher dementia risk, broader and faster cognitive impairment, and greater hippocampal atrophy than both PF individuals and those with SCP. Moreover, the detrimental effects of MCP on dementia risk and hippocampal volume aggravated along with the number of coexisting CP sites. Mediation analyses further revealed that the decline of fluid intelligence in MCP individuals was partially mediated by hippocampal atrophy. Our results suggested that cognitive decline and hippocampal atrophy interact biologically and may underlie the increased risk of dementia associated with MCP.

Manual Lymph Drainage With Progressive Arm Exercises for Axillary Web Syndrome After Breast Cancer Surgery: A Randomized Controlled Trial

OBJECTIVE

This study aimed to determine the effectiveness of a physical therapist-designed program tailored to axillary web syndrome (AWS) in women after breast cancer surgery.

METHODS

A prospective, single-center, assessor-blinded, randomized controlled trial was conducted at the Physiotherapy in Women's Health Research Unit of the Alcalá University (Madrid, Spain). Ninety-six women with AWS were assigned to the physical therapy group (manual lymph drainage [MLD] using resorption strokes and arm exercises as if performing median nerve neurodynamic glide exercises with no neural loading; n = 48) or the control group (standard arm exercises; n = 48), with both groups receiving treatment 3 times a week for 3 weeks. Both interventions included an educational component.

RESULTS

Compared with the control group, the physical therapy group showed significant and clinically relevant improvements in the primary outcome (self-reported pain intensity) at the primary and 3-month follow-ups. Significant and clinically relevant differences between groups were also found in the secondary outcomes (shoulder active range of motion, shoulder disability, and physical and functional aspects of health-related quality of life) at the primary follow-up and in the secondary outcomes as well as the trial outcome index at the 3-month follow-up. No significant differences were found at the 6-month follow-up in either primary or secondary outcomes.

CONCLUSION

The physical therapy program tailored to AWS was found to be effective for AWS symptoms in women after breast cancer surgery, both immediately after the program and after 3 months.

IMPACT

To our knowledge, this is the first appropriately designed study to demonstrate the effectiveness of MLD with progressive arm exercises for AWS. Clinicians and health service providers should consider how to provide survivors of breast cancer with AWS the opportunity to participate in physical therapy programs, including MLD with progressive arm exercises.

LAY SUMMARY

For axillary web syndrome following breast cancer surgery, a physical therapist can design a treatment program including manual lymph drainage and progressive arm exercises, which has been shown to result in reduced pain and improved motion compared with standard arm exercises.

Genome-wide analysis identifies impaired axonogenesis in chronic overlapping pain conditions

Chronic pain is often present at more than one anatomical location, leading to chronic overlapping pain conditions (COPC). Whether COPC represents a distinct pathophysiology from the occurrence of pain at only one site is unknown. Using genome-wide approaches, we compared genetic determinants of chronic single-site vs. multisite pain in the UK Biobank. We found that different genetic signals underlie chronic single-site and multisite pain with much stronger genetic contributions for the latter. Among 23 loci associated with multisite pain, 9 loci replicated in the HUNT cohort, with the DCC netrin-1 receptor (DCC) as the top gene. Functional genomics identified axonogenesis in brain tissues as the major contributing pathway to chronic multisite pain. Finally, multimodal structural brain imaging analysis showed that DCC is most strongly expressed in subcortical limbic regions and is associated with alterations in the uncinate fasciculus microstructure, suggesting that DCC-dependent axonogenesis may contribute to COPC via cortico-limbic circuits.

Do Patients of Chronic Low Back Pain have Psychological Comorbidities?

Background Individuals with chronic pain have been reported to have an increased incidence of psychological morbidities. We aimed to examine the prevalence of anxiety, depression, disability, alexithymia, insomnia, and sleep quality in patients having chronic low back pain (LBP) and study their association with the severity of pain and any disability arising from it. Methods This descriptive study was conducted in a tertiary care teaching hospital setting. Fifty adults with nonspecific LBP of > 6-week duration were included. Study instruments employed were patient health questionnaire-9 for depression, generalized anxiety disorder-7 for anxiety, visual analogue scale (VAS) score for pain, Oswestry disability index (ODI) to assess disability, Toronto alexithymia scale-20 for alexithymia, and insomnia severity index and Pittsburgh sleep quality index for insomnia. Descriptive results were expressed as numbers, means, and proportions. Association study between variables was performed using Fisher's exact test. Results Mean ODI score was 31.54% (95% CI, 26.09-36.99); mean VAS score was 6.08 (95% CI, 5.35-6.81). Insomnia of varying severity was found in 29 patients. Sleep quality was reported as good by 23 patients. One patient had alexithymia. There was significant association between the level of disability and depression, anxiety, insomnia, and sleep quality. The severity of pain had significant association with insomnia but the association with anxiety, depression, alexithymia, and sleep quality was not significant. Conclusions Patients with chronic LBP do have associated psychological comorbidities of varying extent. A "patient-centric" approach when treating patients with chronic LBP is necessary, so that appropriate evaluation of psychiatric and psychosocial comorbidities, sleep problems, and quality of life is done as part of their routine management to ensure the desired outcomes.

Pain, Sleep, and Health-Related Quality of Life after Multidisciplinary Intervention for Chronic Pain

Multidisciplinary pain-management programs have the potential to decrease pain intensity, improve health-related quality of life (HRQOL), and increase sleep quality. In this longitudinal prospective cohort study, the aim was to investigate the long-term effects of multidisciplinary pain rehabilitation interventions in Iceland. More precisely, we (a) explored and described how individuals with chronic pain evaluated their pain severity, sleep, and HRQOL at pre-treatment and at one-year follow-up and (b) examined what predicted the participants' one-year follow-up HRQOL. Seventy-nine patients aged 20-68 years, most of whom were women (85%), responded. The participants scored their pain lower at one-year follow-up (p < 0.001). According to their response, most of them had disrupted sleep, mainly because of pain. One year after the treatment, more participants slept through the night (p = 0.004), and their HRQOL increased. Higher pre-treatment mental component summary (MCS) scores and having pursued higher education predicted higher MCS scores at one-year follow-up, and higher pre-treatment physical component summary (PCS) scores predicted higher PCS scores at one-year follow-up. Sleep problems, being a woman, and having children younger than 18 years of age predicted lower MCS scores at one-year follow-up. These findings are suggestive that patients should be examined with respect to their mental status, and it could be beneficial if they received some professional support after completing the intervention.

From One Pain to Many: The Emergence of Overlapping Pains in Children and Adolescents

OBJECTIVES

The objective of this study was to compare children and adolescents with overlapping chronic pains (OCP) to those with single chronic pains (SCP) among youth presenting in specialized clinical settings, in an effort to identify potential risk factors for developing overlapping pains.

METHODS

A total of 1235 youth ages 8 to 18 seen in a tertiary care multidisciplinary pain clinic or a multidisciplinary headache clinic completed self-report measures of pain, disability, psychological functioning and clinical history and characteristics at the time of initial clinic visit. Information was captured in a chronic pain data repository and accessed for the current study.

RESULTS

Subsequent pain symptoms developed on average 11.9 months (SD=24.5 mo) after onset of the first pain symptom. Compared with patients with SCP, patients with OCP report more medical comorbidity, more developmental issues, and poorer current sleep and school functioning. They also scored significantly higher than patients with SCP on self-reported functional disability, pain catastrophizing, fear of pain, depression, anxiety, and psychological stress and lower quality of life (all Ps<0.001). In multivariate analysis, variables most strongly associated with presenting with OCP were age (odds ratio [OR]: 1.1, P<0.001), having a clinically significant high functional disability (OR: 1.4, P=0.3), and low quality of life (OR: 2.5, P<0.001).

DISCUSSION

Given their tendency toward more psychological and medical comorbidities, patients with OCP may require more intense and diverse treatment approaches. Some early life experiences may be a risk factor for development of OCP. Longitudinal studies are needed to fully evaluate the heightened risk for OCP associated with some of these factors.

Interest of registries in neuropathic pain research

Neuropathic pain is frequent in the general population, with 7 to 10% of adults presenting with chronic neuropathic pain. To date, the gold standard to evaluate treatments is based on randomized controlled trials. Nonetheless, such design is run on a limited sample and for a limited period. Moreover, many treatments will never be compared directly in sufficiently large and representative populations. A way to overcome several of these limitations is to use real-world data. Indeed, the International Association for the Study of Pain (IASP) includes a special interest group focusing on pain registries and promoting the use of such approaches. In this short narrative review, several of the main chronic pain registries are presented. The strengths and weaknesses of this approach are presented. Indication bias is frequent in observational studies because the choice of treatment is generally influenced by the patients' characteristics. However, a propensity score can be computed to adjust for these differences. The use of propensity score is briefly explained. Some data specific to neuropathic pain are discussed.

Association of temporomandibular disorders with pain sensitivity: A cohort study

BACKGROUND

Pain related to temporomandibular disorders (TMD) can be linked with multiple site pain (MSP), and may associate with increased pain sensitivity, more frequently among women than men. The aim of the study was to examine the associations of pressure pain threshold (PPT) and tolerance (PPTo) with TMD and associated MSP in the Northern Finland Birth Cohort 1966 (NFBC1966) study.

METHODS

Altogether 1961 NFBC1966 subjects attended clinical medical and dental examination at the Institute of Dentistry, University of Oulu in 2012-2013. Clinical examinations were carried out using a modified Diagnostic Criteria for TMD protocol (DC/TMD). MSP was defined based on questions regarding body pain sites. Additionally, PPT and PPTo were assessed using algometer measurements. Mann-Whitney U-test and Tobit regression models were used to analyse associations between TMD sub-diagnoses, MSP, PPT and PPTo, stratified by sex. Further models were adjusted with anxiety and depressive symptoms, which were assessed using Hopkins Symptom Checklist-25 (HSCL-25) and two-way interaction terms.

RESULTS

Among females, lower PPT and PPTo were associated with myalgia and arthralgia. Among males, lower PPT and PPTo were associated with MSP-linked TMD. Tobit regression analysis showed significantly lower PPT and PPTo values in the myalgia and arthralgia subgroups among female TMD subjects. Among females, disc displacement with reduction had an inverse association with PPT and PPTo. Among males, lower PPTo was associated with degenerative joint disease and MSP-linked TMD.

CONCLUSIONS

The pain regulatory mechanisms behind TMD act differently between the genders as local TMD among females and MSP-linked TMD among males were associated with pain sensitivity.

SIGNIFICANCE

The study shows that there are differences in the associations of painful TMD with pressure pain tolerance, pressure pain sensitivity and MSP between male and female subjects.

Chronic primary or secondary non-inflammatory musculoskeletal pain is associated with disrupted sexual function and relationships: a systematic review

OBJECTIVE

Evidence points to the impact of chronic musculoskeletal pain conditions on sexual function, yet there is little systematic appraisal and synthesis of evidence examining these associations across non-inflammatory conditions. We aimed to systematically review evidence surrounding the association between chronic primary and secondary musculoskeletal pain with intimate relationships and sexual function.

METHODS

Four electronic databases were searched from 1^st January 1990 to 5^th September 2019 for cross-sectional or prospective epidemiologic and qualitative studies among cohorts with chronic primary or secondary non-inflammatory musculoskeletal pain, defined by ICD-11 classification criteria.

RESULTS

Fifty-one eligible studies were included (46 quantitative, 3 qualitative, 2 mixed-methods designs). Sample sizes ranged from 13 to 12,377 and mean age from 32.6 to 69.2 years. Cross-sectional controlled cohort studies consistently reported poorer sexual function outcomes among cohorts with pain relative to comparison groups. Of 15 studies reporting outcomes for the Female Sexual Function Index, 14 demonstrated mean scores ≤26.55 for the pain group, indicating sexual dysfunction. In four studies reporting the International Index of Erectile Function, the pain cohorts demonstrated consistently lower mean subscale scores and the erectile function subscale scores were ≤25.0, indicating erectile dysfunction. Three key themes emerged from a meta-synthesis of qualitative studies: impaired sexual function; compromised intimate relationships; and impacts of pain on sexual identity, body image and self-worth.

CONCLUSION

Sexual dysfunction and negative impacts on intimate relationships are highly prevalent among people with chronic non-inflammatory musculoskeletal pain. Consideration of these associations is relevant to the delivery of holistic, person-centred musculoskeletal pain care.

Pregabalin prescribing patterns in Australian general practice, 2012-2018: a cross-sectional study

BACKGROUND

In 2013 pregabalin was subsidised by Australia's Pharmaceutical Benefits Scheme (PBS) for neuropathic pain. Since the subsidy, pregabalin prescribing has been increasing in Australia and so has related harm. There are concerns it is being prescribed for indications other than neuropathic pain, which have little evidence of efficacy.

AIM

To describe pregabalin prescribing in Australian general practice.

DESIGN & SETTING

A cross-sectional study of patients attending 445 general practice sites in the national MedicineInsight database from March 2012-February 2018.

METHOD

The following aspects were calculated: the proportion of prescriptions that were for pregabalin per year; the prevalence of pain conditions in patients prescribed pregabalin; and same-day prescribing of pregabalin with opioids or benzodiazepines.

RESULTS

Prescribing increased from 13 per 10 000 to 104 per 10 000 prescriptions between 2012-2013 and 2017-2018. A total of 1 891 623 patients were identified of whom 114 123 (6.0%) were prescribed pregabalin; 49.7% (n = 56 772) had a recorded diagnosis of neuropathic pain. Among people prescribed pregabalin without a recorded diagnosis of neuropathic pain, 43.5% (n = 24 927) had a diagnosis of back problems, 8.8% (n = 5073) chronic pain, and 26.4% (n = 30 146) had no pain diagnosis. Pregabalin was prescribed the same day as an opioid to 38.1% of patients (95% confidence interval [CI] = 37.1% to 39.1%) and a benzodiazepine to 13.1% of patients (95% CI = 12.5% to 13.7%). Patients with a diagnosis of chronic pain had the highest rate of same-day prescribing of pregabalin with an opioid (70.4%, 95% CI = 68.9% to 71.9%) or a benzodiazepine (25.8%, 95% CI = 24.2% to 27.4%) CONCLUSION: Substantial increases in pregabalin prescribing were identified in Australian general practice, but only half of patients had a neuropathic pain diagnosis recorded, the only approved indication for subsidy. High rates of same-day prescribing with opioids and benzodiazepines may put patients at increased risk of harm.

Distribution and prevalence of musculoskeletal pain co-occurring with persistent low back pain: a systematic review

BACKGROUND

Co-occurring musculoskeletal pain is common among people with persistent low back pain (LBP) and associated with more negative consequences than LBP alone. The distribution and prevalence of musculoskeletal pain co-occurring with persistent LBP has not been systematically described, which hence was the aim of this review.

METHODS

Literature searches were performed in MEDLINE, Embase, CINAHL and Scopus. We considered observational studies from clinical settings or based on cohorts of the general or working populations involving adults 18 years or older with persistent LBP (≥4 wks) and co-occurring musculoskeletal pain for eligibility. Study selection, data extraction and risk of bias assessment were carried out by independent reviewers. Results are presented according to study population, distribution and location(s) of co-occurring pain.

RESULTS

Nineteen studies out of 5744 unique records met the inclusion criteria. Studies were from high-income countries in Europe, USA and Japan. A total of 34,492 people with persistent LBP were included in our evidence synthesis. Methods for assessing and categorizing co-occurring pain varied considerably between studies, but based on the available data from observational studies, we identified three main categories of co-occurring pain - these were axial pain (18 to 58%), extremity pain (6 to 50%), and multi-site musculoskeletal pain (10 to 89%). Persistent LBP with co-occurring pain was reported more often by females than males, and co-occurring pain was reported more often in patients with more disability.

CONCLUSIONS

People with persistent LBP often report co-occurring neck pain, extremity pain or multi-site pain. Assessment of co-occurring pain alongside persistent LBP vary considerable between studies and there is a need for harmonisation of measurement methods to advance our understanding of how pain in different body regions occur alongside persistent LBP.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017068807 .

A Nationwide Cross-Sectional Study of Self-Reported Adherence and Factors Associated with Analgesic Treatment in People with Chronic Pain

This study aims to shed light on the frequency and associated factors of self-reported adherence to analgesic treatment among chronic pain (CP) patients in the Spanish population. A nationwide cross-sectional study was performed of 1066 Spanish adults, of whom 251 suffered from CP and 168 had been prescribed analgesic treatment. Adherence was assessed using a self-reported direct questionnaire and related factors were collected. Descriptive and bivariate analyses were conducted. Among the 23.5% (95% CI: 21.0–26.2%) of the sample with CP, 66.9% (95% CI: 60.7–72.7%) were taking analgesic treatment prescribed by a doctor, and 81.0% (95% CI: 74.2–86.6%) said they took the treatment as the doctor indicated. However, 17.6% forgot to take the medication, 11% overused them when in great pain, 46.3% stopped the treatment when feeling better and 33.3% when feeling worse, and 7.3% stopped taking them for financial reasons. Higher intensity of pain, polymedication, administration route (injection/patches) and some patient-related factors were associated with self-perceived adherence to treatment. Most Spanish people with CP consider that they are adherent to their analgesic treatment. However, their behavior presents contradictions. It would be advisable for professionals to inform patients about appropriate behavior regarding their therapy recommendations, and to explore potential factors related to non-adherence. This could contribute to improving pain control.

EQ-5D-5L and SF-6Dv2 utility scores in people living with chronic low back pain: a survey from Quebec

OBJECTIVE

To describe how chronic low back pain (CLBP) impacts on utility scores and which patients' characteristics most affect these scores in the province of Quebec.

SETTINGS

Province of Quebec, Canada.

PARTICIPANTS

569 adult patients with CLBP.

METHODS AND OUTCOMES

An online survey on low back pain was conducted between October 2018 and January 2019. The EuroQol Five Dimensions (EQ-5D-5L) and the Short Form Six Dimensions version 2 (SF-6Dv2) are two generic preference-based measures used to evaluate health-related quality of life (HRQoL) and provide quality-adjusted life-year utility values.

RESULTS

The number of subjects who agreed to participate was 610, but 41 were excluded because 8 had low back pain for less than 3 months and 33 did not start the survey. A total of 569 subjects were analysed, but only 410 completed the survey up to the EQ-5D-5L or SF-6Dv2 sections. Median (range) of EQ-5D-5L was 0.622 (-0.072 to 0.905), and mean (range) of SF-6Dv2 and EQ-Visual Analogue Scale was 0.561 (0.301-0.829) and 51.0 (0-100), respectively. In all multivariate models, health or life satisfaction increased the health utility score, while pain reduced it. Co-occurring health problems were present for a majority (68%) of participants, mainly fatigue/insomnia (57.4%), musculoskeletal disorder (56.2%) and mental disorder (44%).

CONCLUSION

This study provided utility scores with EQ-5D-5L and SF-6Dv2 in patients with CLBP in Quebec, and results were similar to other studies conducted in different settings. These values were well below those reported in the Quebec general population and highlight the association between CLBP and HRQoL.

Longitudinal associations of changes in physical activity and TV viewing with chronic musculoskeletal pain in Brazilian schoolteachers

This study analyzed the longitudinal association of changes in leisure-time physical activity (LTPA) practice and television viewing (TV viewing) with chronic musculoskeletal pain (CMP). The data about LTPA, TV viewing, and CMP were obtained in 2012 and after 24 months through individual interviews with schoolteachers from elementary and secondary education public schools in a large city in the southern region of Brazil. The statistical analysis was performed using generalized estimating equation regression models adjusted for sex, age, body mass index and depression. A total of 527 schoolteachers were studied, among which 66.6% were women, and the median age was 42 years (interquartile range: 34 to 49). A total of 170 (32.3%) participants reported CMP at baseline and 130 (24.7%) at follow-up. Both LTPA and TV viewing were independently and significantly associated with CMP regardless of all adjustment variables. Concretely, increasing LTPA by 60 minutes/week was associated with a 6.2% lower likelihood of CMP, and increasing TV viewing by 30 minutes/day was associated with a 5.1% higher likelihood of having CMP among the participants. In summary, this study showed that LTPA and TV viewing have independent and opposite relationships with the longitudinal risk of CMP, which suggests that the potential benefits obtained from practicing more LTPA are insufficient to compensate for the potential detrimental effect of viewing TV for longer with respect to the CMP.

Predicting SF-6Dv2 utility scores for chronic low back pain using the Oswestry Disability Index and Roland-Morris Disability Questionnaire

Background: Generic preference-based measures are used to evaluate disability and health-related quality of life (HRQoL). Objective: To evaluate if Short Form Six-Dimensions (SF-6Dv2) is correlated with specific current questionnaires used in chronic low back pain (CLBP) and if a predictive equation of SF-6Dv2 could be established. Methods: Between October 2018 and January 2019, an online survey on CLBP was conducted. HRQoL was measured with two specific questionnaires, i.e. Oswestry Disability Index (ODI) and Roland-Morris Disability Questionnaire (RMDQ), and with the new version of the SF-6Dv2 as a generic preference-based measure. Results: 402 subjects completed at least two of the three HRQoL questionnaires. Mean (95% confidence interval) of SF-6Dv2, ODI, or RMDQ were, respectively, 0.561 (0.553-0.569), 43.7 (42.1-45.2), and 10.3 (9.8-10.8). SF-6Dv2 was moderately correlated with ODI and RMDQ (r = -0.635 and r = -0.542, p < 0.001). The best model to predict SF-6Dv2 explained 50.6% of variability and included ODI. The correlation between actual and predicted SF-6Dv2 was 0.71. Conclusion: This study demonstrated that SF-6Dv2 was moderately correlated with ODI and RMDQ and that ODI was a better predictor. There was a strong correlation between actual and predicted SF-6Dv2 from multivariate models. These results suggest that the model can be used in similar studies to estimate the SF-6Dv2 when it was not measured.

Does Operative Intervention Provide Early Pain Relief for Patients With Unilateral Sacral Fractures and Minimal or No Displacement?

OBJECTIVES

To compare pain after operative versus nonoperative pelvic ring injuries with unilateral sacral fractures.

DESIGN

Prospective, multicenter, observational.

SETTING

Sixteen trauma centers.

PATIENTS/PARTICIPANTS

Skeletally mature patients with pelvic ring injury and minimally displaced unilateral zone 1 or 2 sacral fractures and without anteroposterior compression injuries.

MAIN OUTCOME MEASUREMENTS

Pelvic displacement was documented on injury plain radiographs and computed tomography scans; a 10 point Visual Analog Scale (VAS) was used to evaluate pain was obtained in the anterior and posterior pelvic ring during the time of union (12 weeks).

RESULTS

One hundred ninety-four patients with unilateral sacral fractures displaced less than 5 mm, mean age of 38.7, and mean Injury Severity Score of 14.5 were included. Ninety-nine percent had lateral compression injuries, and 62% were in zone 1. Seventy-four percent were treated nonoperatively. Nonoperative patients had more zone 1 fractures (71%, P = 0.004). Nonoperative patients reported mean VAS 2.7 points higher in the posterior pelvis (P = 0.01) and 1.9 points higher anteriorly (P = 0.11) 24 hours after injury compared with patients treated operatively. After 3 months, nonoperative patients reported higher VAS scores than operative patients: 4.0 versus 2.9 posteriorly (P = 0.019) and 3.2 versus 2.3 anteriorly (P = 0.035).

CONCLUSIONS

For sacrum fractures with minimal or no displacement, slight differences in the VAS were noted within 24 hours after injury or surgery, but limited differences were seen at 3 months for either operatively treated minimally or undisplaced sacrum fractures. It is unknown whether this represents clinical relevance. These differences were below the minimally important clinical difference for VAS scores for other orthopaedic conditions.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Chronic pain: a review of its epidemiology and associated factors in population-based studies

Chronic pain is a common, complex, and distressing problem that has a profound impact on individuals and society. It frequently presents as a result of a disease or an injury; however, it is not merely an accompanying symptom, but rather a separate condition in its own right, with its own medical definition and taxonomy. Studying the distribution and determinants of chronic pain allows us to understand and manage the problem at the individual and population levels. Targeted and appropriate prevention and management strategies need to take into account the biological, psychological, socio-demographic, and lifestyle determinants and outcomes of pain. We present a narrative review of the current understanding of these factors.

Examining the Adjustment Patterns of Adults With Multiple Chronic Pain Conditions and Multiple Pain Sites: More Pain, No Gain

The present study examined how multiple chronic pain conditions and pain sites are associated with sociodemographics, chronic pain adjustment profiles, and emotional distress. A total of 2,407 individuals who reported at least 6 months of having consistent pain severity, pain interference, and/or emotional burden due to pain were recruited through random digit dialing across the United States. Participants' chronic pain adjustment profiles (ie, pain intensity, pain interference, emotional burden, pain catastrophizing, pain coping, pain attitudes, and social resources) were assessed. Anxiety and depressive symptoms were also measured using a subsample of 181 participants who provided 3-month follow-up data. More than 60% of individuals with chronic pain reported having multiple pain conditions. Middle-aged single women with fibromyalgia, disability and of low socioeconomic status reported a greater number of pain conditions and pain sites. Structural equation modeling revealed that a higher number of pain conditions and sites were associated with more dysfunctional chronic pain adjustment profiles. The subsample analyses showed that reporting a greater number of pain conditions predicted a higher level of depression and anxiety 3 months later, controlling for pain-related anxiety and depressive symptoms, pain severity and interference at baseline. Having multiple pain conditions and sites may represent a psychosocial barrier to successful adjustment to chronic pain. PERSPECTIVE: This article argues for the importance of assessing the number of co-occurring chronic pain conditions and bodily areas that are affected by pain in both pain research and clinical settings. Measuring and incorporating such information could potentially enhance our nascent understanding of the adjustment processes of chronic pain.

Improvement in Work Ability, Psychological Distress and Pain Sites in Relation to Low Back Pain Prognosis: A Longitudinal Observational Study in Primary Care

STUDY DESIGN

Prospective observational study pooled from two clinical cohorts.

OBJECTIVE

To investigate the longitudinal relation between multisite pain, psychological distress, and work ability with disability, pain, and quality of life.

SUMMARY OF BACKGROUND DATA

Knowledge of prognostic factors is essential for better management of patients with low back pain (LBP). All domains of the biopsychosocial model have shown prognostic value; however, clinical studies rarely incorporate all domains when studying treatment outcome for patients with LBP.

METHODS

A total of 165 patients with nonspecific LBP seeking primary care physiotherapy were included. Mixed-effects models were used to estimate longitudinal relations between the exposure variables and concurrent measures of outcomes at baseline and 3 months. Logistic regression was used to estimate odds ratios for minimal important difference in outcome.

RESULTS

Higher work ability was associated with less disability -2.6 (95% confidence interval [CI]: -3.3, -2.0), less pain: -0.4 (95% CI: -0.5, -0.3), and higher quality of life 0.03 (95% CI: 0.02, 0.04). Higher psychological distress and number of pain sites were associated with higher disability: 10.9 (95% CI: 7.7, 14.1) and 2.3 (95% CI: 1.4, 3.2) higher pain: 1.9 (95% CI: 1.3, 2.5) and 0.4 (95% CI: 0.2, 0.5), and lower quality of life: -0.1 (95% CI: -0.2, -0.1) and -0.02 (95% CI: -0.03, -0.01), respectively. Improvement in work ability showed consistent associations with successful outcome for disability (odds ratio [OR]: 4.8, 95% CI: 1.3, 18.1), pain (OR: 3.6, 95% CI: 1.1, 12.1), and quality of life (OR: 4.5, 95% CI: 1.4, 15.1) at 3 months. Reduced psychological distress was associated with improvement in pain only (OR 4.0, 95% CI: 1.3, 12.3).

CONCLUSION

More pain sites, higher psychological distress, or lower work ability showed higher disability, more pain, and lower quality of life in patients with LBP. Only improvement in work ability was consistently related to successful outcomes.

LEVEL OF EVIDENCE

2.