Economic burden of chronic pain

3,3-Dibromoflavanone, a synthetic flavonoid derivative for pain management with antidepressant-like effects and fewer side effects than those of morphine in mice

In the pursuit of new lead compounds with fewer side effects than opioids, the novel synthetic phytochemical core, 3,3-dibromoflavanone (3,3-DBF), has emerged as a promising candidate for pain management. Acute assays demonstrated dose-dependent central and peripheral antinociceptive activity of 3,3-DBF through the μ-opioid receptor. This study aimed to explore repeated administration effects of 3,3-DBF in mice and compare them with morphine. Mice were treated with 3,3-DBF (30 mg/kg), morphine (6 mg/kg), or vehicle for 10 days, alongside single-treatment groups. Unlike morphine, 3,3-DBF demonstrated antinociceptive effects in the hot plate test without inducing tolerance. Locomotor activity and motor coordination tests (evaluated through the inverted screen and rotarod tests) revealed no significant differences between the 3,3-DBF-treated and control groups. The gastrointestinal transit assay indicated that 3,3-DBF did not induce constipation, in contrast to morphine. Furthermore, withdrawal signs assessed with the Gellert-Holtzman scale were not comparable to morphine. Additionally, 3,3-DBF exhibited antidepressant-like activity, reducing immobility time in the forced swimming and tail suspension tests, akin to imipramine. In summary, 3,3-DBF demonstrated antinociceptive effects without inducing tolerance or dependence and exhibited antidepressant properties. These findings highlight the potential of 3,3-DBF as a promising therapeutic agent for pain management and its comorbidities, offering advantages over morphine by minimizing side effects.

Cells and circuits for amygdala neuroplasticity in the transition to chronic pain

Maladaptive plasticity is linked to the chronification of diseases such as pain, but the transition from acute to chronic pain is not well understood mechanistically. Neuroplasticity in the central nucleus of the amygdala (CeA) has emerged as a mechanism for sensory and emotional-affective aspects of injury-induced pain, although evidence comes from studies conducted almost exclusively in acute pain conditions and agnostic to cell type specificity. Here, we report time-dependent changes in genetically distinct and projection-specific CeA neurons in neuropathic pain. Hyperexcitability of CRF projection neurons and synaptic plasticity of parabrachial (PB) input at the acute stage shifted to hyperexcitability without synaptic plasticity in non-CRF neurons at the chronic phase. Accordingly, chemogenetic inhibition of the PB→CeA pathway mitigated pain-related behaviors in acute, but not chronic, neuropathic pain. Cell-type-specific temporal changes in neuroplasticity provide neurobiological evidence for the clinical observation that chronic pain is not simply the prolonged persistence of acute pain.

Exercise Training for Chronic Pain: Available Evidence, Current Recommendations, and Potential Mechanisms

Chronic pain conditions pose a significant global burden of disability, with epidemiological data indicating a rising incidence. Exercise training is commonly recommended as a standalone or complementary approach for managing various chronic pain conditions like low back pain, osteoarthritis, rheumatoid arthritis, fibromyalgia syndrome, and neuropathic pain. Regardless of the specific condition or underlying cause (e.g., autoimmune disease, chronic inflammation), exercise training consistently leads to moderate to large reductions in pain. Moreover, exercise yields numerous benefits beyond pain alleviation, including small-to-moderate improvements in disability, quality of life, and physical function. Despite its efficacy, there is a lack of comprehensive research delineating the optimal intensity, duration, and type of exercise for maximal benefits; however, evidence suggests that sustained engagement in regular exercise or physical activity is necessary to achieve and maintain reductions in both clinical pain intensity ratings and the level that pain interferes with activities of daily living. Additionally, the precise mechanisms through which exercise mitigates pain remain poorly understood and likely vary based on the pathophysiological mechanisms underlying each condition.

Multidisciplinary strategies to treat painful mononeuropathies in the upper extremity: from lab to bedside

Neuropathic pain in the upper extremity is a serious problem, commonly involving relatively young patients. The pain causes loss of function and productivity, changes a patient's lifestyle and can progress into a chronic pain syndrome with secondary psychosocial co-morbidities. Treating patients with a painful mononeuropathy remains challenging, with a monodisciplinary approach often having limited treatment efficacy. This narrative review discusses how to deal with this challenge in the treatment of patients with peripheral nerve injury pain, addressing the four important pillars: (1) diagnosing a painful mononeuropathy; (2) clinical pain phenotyping; (3) personalized pain treatment; and (4) using a multidisciplinary team approach.

Photobiomodulation inhibits neuronal firing in the superficial but not deep layer of a rat spinal dorsal horn

Photobiomodulation (PBM) has attracted attention as a treatment for chronic pain. Previous studies have reported that PBM of the sciatic nerve inhibits neuronal firing in the superficial layers (lamina I-II) of the spinal dorsal horn of rats, which is evoked by mechanical stimulation that corresponds to noxious stimuli. However, the effects of PBM on the deep layers (lamina III-IV) of the spinal dorsal horn, which receive inputs from innocuous stimuli, remain poorly understood. In this study, we examined the effect of PBM of the sciatic nerve on firing in the deep layers of the spinal dorsal horn evoked by mechanical stimulation. Before and after PBM, mechanical stimulation was administered to the cutaneous receptive field using 0.6-26.0 g von Frey filaments (vFFs), and vFF-evoked firing in the deep layers of the spinal dorsal horn was recorded. The vFF-evoked firing frequencies were not altered after the PBM for any of the vFFs. The inhibition rate for 26.0 g vFF-evoked firing was approximately 13 % in the deep layers and 70 % in the superficial layers. This suggests that PBM selectively inhibits the transmission of pain information without affecting the sense of touch. PBM has the potential to alleviate pain while preserving the sense of touch.

Exercise-induced hypoalgesia in chronic neck pain: A narrative review

Chronic neck pain (CNP) is a worldwide health problem with several risk factors. One of the most widely used treatments for managing this condition is therapeutic exercise, which could generate a response called exercise-induced hypoalgesia (EIH). There is no consensus on the best exercise modality to induce hypoalgesia. Therefore, this review aims to analyze and synthesize the state-of-the-art about the hypoalgesic effect of exercise in subjects with CNP. We included articles on EIH and CNP in patients older than 18 years, with pain for more than three months, where the EIH response was measured. Articles that studied CNP associated with comorbidities or measured the response to treatments other than exercise were excluded. The studies reviewed reported variable results. Exercise in healthy subjects has been shown to reduce indicators of pain sensitivity; however, in people with chronic pain, the response is variable. Some investigations reported adverse effects with increased pain intensity and decreased pain sensitivity, others found no clinical response, and some even reported EIH with decreased pain and increased sensitivity. EIH is an identifiable, stimulable, and helpful therapeutic response in people with pain. More research is still needed on subjects with CNP to clarify the protocols and therapeutic variables that facilitate the EIH phenomenon. In addition, it is necessary to deepen the knowledge of the intrinsic and extrinsic factors that influence EIH in people with CNP.

Development of a Multimodal, Personalized Intervention of Virtual Reality Integrated Within Physiotherapy for Patients With Complex Chronic Low-Back Pain

Background

Chronic low-back pain (CLBP) is the leading cause of years lived with disability. Physiotherapy is the most common treatment option for CLBP, but effects are often unsatisfactory. Virtual reality (VR) offers possibilities to enhance the effectiveness of physiotherapy treatment. Primary aim was to develop and test a personalized VR intervention integrated within a physiotherapy treatment for patients with CLBP.

Methods

This study describes an intervention development process using mixed methods design that followed the Medical Research Council (MRC) framework. This involved a cocreation process with patients, physiotherapists, and researchers. A draft intervention was constructed based on a literature review and focus groups, and subsequently tested in a feasibility study and evaluated in focus groups. Focus group data were analyzed using thematic analysis. This intervention development process resulted in a final intervention.

Results

Focus group data showed that VR and physiotherapy can strengthen each other when they are well integrated, and that VR needs to be administered under the right conditions including flawless technology, physiotherapists with sufficient affinity and training, and the right expectations from patients. The draft intervention was considered feasible after evaluation by four patients and three physiotherapists and was further complemented by expanding the training for physiotherapists and improving the protocols for physiotherapists and patients. The final intervention consisted of a 12-week physiotherapy treatment with three integrated VR modules: pain education, physical exercise, and relaxation.

Conclusion

Using the MRC framework in cocreation with the end users, a personalized VR intervention integrated within a physiotherapy treatment for patients with CLBP was developed. This intervention was found to be feasible and will subsequently be evaluated for (cost-)effectiveness in a cluster randomized controlled trial.

Effects of Different Mind-body Exercises in Managing Chronic Pain of Older Adults: A Network Meta-analysis of Randomized Trials

INTRODUCTION

Mind-body exercises (MBEs) were shown to be effective in managing chronic pain among older adults in several recent studies. However, the differences in the effects of different MBEs remained unclear.

OBJECTIVE

To compare the effects of different MBEs in managing chronic pain in older adults.

METHODS

Eight databases were searched for studies published between 2012 and 2023, and 14 studies were included in this systematic review and network meta-analysis (NMA). The NMA was performed using R and Metainsight.

RESULTS

Results showed that tai chi and yoga were effective in alleviating chronic pain, but their effects were not superior to traditional physical exercises and other MBEs. In addition, none of the MBEs were shown to be effective in mitigating chronic pain-related disabilities.

CONCLUSION

Tai chi and yoga can be used for relieving chronic pain in older adults; however, MBE programs alone were not sufficient to mitigate chronic pain-related disabilities.

Temporary Peripheral Nerve Stimulation as Treatment for Chronic Pain

INTRODUCTION

Chronic pain is a growing problem across the world, and in the midst of an opioid epidemic, it is imperative that alternative treatment measures are identified to help alleviate the pain experienced by these patients. Chronic pain greatly affects ones quality of life and many patients do not experience adequate relief with conventional treatment measures. The purpose of this retrospective analysis is to assess the efficacy of peripheral nerve stimulation (PNS) therapy in adult patients suffering from chronic pain refractory to conventional treatment measures who underwent therapy on various anatomical locations.

METHODS

This retrospective analysis consisted of data collected from electronic health records for n = 89 patients who underwent PNS therapy. Data collected relates to patient age, sex, weight, height, body mass index (BMI), diagnosis, targeted nerves, follow-up encounters, pain scores from before and after PNS therapy, and duration of improvement. Statistical analysis used SPSS software, version 26 (IBM), using a paired t test to assess significance between pre and post PNS therapy pain scores. P values were significant if found to be ≤ 0.05. Further analysis assessed the correlation between age and BMI with visual analog scale (VAS) pain improvement and subjective percentage pain relief.

RESULTS

The mean pre-operative (pre-op) pain score before PNS therapy was 6.36 (standard deviation (SD) = 2.18, SEM = 0.23) and the mean post-operative (post-op) pain score after PNS therapy was 4.19 (SD = 2.70, SEM = 0.29). The mean patient-reported percent improvement in pain following PNS therapy was 49.04% (SD = 34.79). The improvement in pain scores between pre-op and post-op was statistically significant (M = 2.17, SD = 2.82, SEM = 0.30, t(88) = 7.26, p < .001), 95% confidence interval (CI) [1.57, 2.76]. The mean duration of improvement for patients was 123 days after therapy initiation (min = 6, max = 683, SD = 126).

CONCLUSIONS

This study demonstrated the potential role for PNS therapy in improving patient-reported pain levels for various neuropathies, targeting various nerves. With PNS therapy's use as a chronic pain treatment and available research being limited, further study needs to be done on the efficacy of PNS therapy for pain management and complications associated with PNS device placements at various locations.

Psychological, social and academic functioning in university students with chronic pain: A systematic review

OBJECTIVE

Chronic pain is a prevalent health issue among young adults; however, there is limited understanding on how it affects university students. This is the first systematic review of evidence relating to the association between chronic pain and psychological, social and academic functioning in university students. Participants: Four databases were searched for relevant published studies. Data from 18 studies including 10,069 university students, of which 2895 reported having chronic pain, were included in the synthesis. Methods: Due to heterogeneity of data and methodologies, meta-analysis was not possible; therefore, data were synthesized narratively. Results: Our findings showed that students with chronic pain have poorer psychological, social and academic functioning and quality of life, compared to students without chronic pain. Conclusions: These findings suggest that chronic pain presents a challenge in university settings. Research is urgently needed to enable an understanding of how universities can support students who experience chronic pain.

Content and Quality of Mobile Apps for the Monitoring of Musculoskeletal or Neuropathic Pain in Australia: Systematic Evaluation

Background

Mobile apps offer a potential mechanism for people with persistent pain to monitor pain levels conveniently within their own environment and for clinicians to remotely monitor their patients' pain. However, the quality of currently available apps and the usefulness of included features from a clinical perspective are not known.

Objective

The aim of this study was to examine the content and quality of currently available smartphone apps designed for monitoring the intensity or presence of musculoskeletal or neuropathic pain.

Methods

A systematic search was performed in the Australian Apple and Google Play stores. Apps were included if they were designed to monitor the intensity or presence of musculoskeletal or neuropathic pain and were available in the English language within the Australian app stores. Data pertaining to the intended use of the app and clinical population were extracted by using a custom-designed data extraction form, and app quality was assessed by using the 23-item Mobile App Rating Scale.

Results

Of the 2190 apps screened, 49 met the inclusion criteria. Apps were primarily designed for adult users (36/49, 73%) with nonspecific musculoskeletal or neuropathic pain conditions, arthritis, and joint pain. All apps monitored pain intensity, with almost half (23/49, 47%) also specifying pain location. Overall, the mean quality scores from the Mobile App Rating Scale ranged from 1.5 to 4.4 (out of 5.0). Between 20% (10/49) and 22% (11/49) of apps involved clinicians, consumers, or both in their development, and 20% (10/49) had published literature related to the development or use of the app in clinical scenarios. Although 71% (35/49) had data sharing features, only 5 apps enabled client-clinician communication through the app.

Conclusions

The overall quality of mobile apps that are currently available for monitoring pain intensity is acceptable. Presently, mobile apps for remote pain monitoring lack functionality for clinicians to view data between consults. Both users and clinicians should be aware of the limitations of these apps and make informed choices in using or recommending apps that best suit the clinical need.

Impact of COVID-19 pandemic on chronic pain and opioid use in marginalized populations: A scoping review

Introduction

The COVID-19 pandemic has had a variable effect on vulnerable populations, including patients with chronic pain who rely on opioid treatment or have comorbid opioid use disorder. Limited access to care due to isolation measures may lead to increased pain severity, worse mental health symptoms, and adverse opioid-related outcomes. This scoping review aimed to understand the impact of the COVID-19 pandemic on the dual epidemics of chronic pain and opioids in marginalized communities worldwide.

Methods

Searches of primary databases including PubMed, Web of Science, Scopus, and PsycINFO were performed in March 2022, restricting the publication date to December 1, 2019. The search yielded 685 articles. After title and abstract screening, 526 records were screened by title and abstract, 87 through full-text review, of which 25 articles were included in the final analysis.

Results

Our findings illuminate the differential distribution of pain burden across marginalized groups and how it serves to heighten existing disparities. Service disruptions due to social distancing orders and infrastructural limitations prevented patients from receiving the care they needed, resulting in adverse psychological and physical health outcomes. Efforts to adapt to COVID-19 circumstances included modifications to opioid prescribing regulations and workflows and expanded telemedicine services.

Conclusion

Results have implications for the prevention and management of chronic pain and opioid use disorder, such as challenges in adopting telemedicine in low-resource settings and opportunities to strengthen public health and social care systems with a multidisciplinary and multidimensional approach.

Pain prevalence and chronicity in a developing country in Latin America: a population-based survey in Lima, Peru

Background: No population-based epidemiological studies have estimated pain prevalence and its characteristics in Peru. Patients & methods: A representative sample of adults aged over 18 years (n = 502) living in metropolitan Lima, Peru was enrolled. We analyzed prevalence data of pain in the last 3 months and other pain-related characteristics. Results: Pain prevalence was 65.3% (95% CI: 57.7-70.4%). Chronic pain prevalence was 38.5% (95% CI: 33.5-44.0%) and acute pain prevalence was 24.8% (95% CI: 20.7-29.0%). In participants with chronic pain, almost half (55.7%) reported having not used any medication. Conclusion: Pain is prevalent in this population and our results suggest high undertreatment rates.

Cross-Country Differences in Pain Medication Before and After Spinal Cord Stimulation: A Pooled Analysis of Individual Patient Data From Two Prospective Studies in the United Kingdom and Belgium

OBJECTIVES

Spinal cord stimulation (SCS) can reduce the need for opioids; however, the influence on the full spectrum of pain medication is less known. The aims of this study were to explore general prescription practices for patients scheduled for SCS, potential differences in prescriptions between Belgium and United Kingdom, and the influence of SCS on pain medication.

MATERIALS AND METHODS

Individual patient data from the TRIAL-STIM study in the United Kingdom and DISCOVER in Belgium were pooled. Medication use was collected before SCS and three months after SCS from 180 chronic pain patients. The Medication Quantification Scale III (MQS) was used to calculate a total score for medication use, as well as subscores for several classes. Differences in prescription practices between United Kingdom and Belgium were evaluated with two-sided Wilcoxon tests. To evaluate differences in medication use after three months of SCS between United Kingdom and Belgium, Tweedie-generalized linear models were calculated.

RESULTS

There was a statistically significant difference (-6.40 [95% CI from -3.40 to -9.10]) between the median total MQS score in United Kingdom and Belgium before SCS. Additionally, a significant difference was found for nonsteroidal anti-inflammatory drugs (NSAIDs) (-3.40 [95% CI -3.40 to -6.80]), neuropathic agents (-2.30 [95% CI -0.40 to -3.80]), and benzodiazepines (1.83e^-05 [95% CI 2.64^-05 to 7.45^-05]) between United Kingdom and Belgium, before SCS. Tweedie-generalized models revealed a statistically significant interaction between country and time for MQS, neuropathic agents, and opioids.

CONCLUSIONS

Our combined analysis revealed differences in prescription practice in patients scheduled for SCS implantation between Belgium and United Kingdom. NSAIDs and neuropathic mood agents are more frequently used in the United Kingdom, presumably due to easier access to repeat prescriptions and over the counter medications. After three months of SCS, a decrease in medication use is observed in both countries, with higher reductions in Belgium, presumably due to strict regulations concerning reimbursement criteria.

A Bayesian model for chronic pain

The perceiving mind constructs our coherent and embodied experience of the world from noisy, ambiguous and multi-modal sensory information. In this paper, we adopt the perspective that the experience of pain may similarly be the result of a probabilistic, inferential process. Prior beliefs about pain, learned from past experiences, are combined with incoming sensory information in a Bayesian manner to give rise to pain perception. Chronic pain emerges when prior beliefs and likelihoods are biased towards inferring pain from a wide range of sensory data that would otherwise be perceived as harmless. We present a computational model of interoceptive inference and pain experience. It is based on a Bayesian graphical network which comprises a hidden layer, representing the inferred pain state; and an observable layer, representing current sensory information. Within the hidden layer, pain states are inferred from a combination of priors p(pain), transition probabilities between hidden states p(paint+1∣paint) and likelihoods of certain observations p(sensation∣pain). Using variational inference and free-energy minimization, the model is able to learn from observations over time. By systematically manipulating parameter settings, we demonstrate that the model is capable of reproducing key features of both healthy- and chronic pain experience. Drawing on mathematical concepts, we finally simulate treatment resistant chronic pain and discuss mathematically informed treatment options.

A national survey of publicly funded chronic pain management services in Ireland

BACKGROUND

Chronic pain management services have historically been under-resourced in Ireland. There is no agreed model of care for chronic pain management services in Ireland. Previous studies have assessed the extent of services in Ireland without examining waiting times for access to services.

AIMS

This study aimed to quantify the extent of, geographical distribution of and waiting times for access to publicly funded chronic pain management services in Ireland.

METHODS

Using the British Pain Society's Core Standards for Pain Management Services in the UK (2015) and International Association for the Study of Pain (IASP) recommendations, a questionnaire was devised. Publically funded departments in Ireland were contacted and questionnaires completed. Waiting list data was publicly available and obtained from the National Treatment Purchase Fund website.

RESULTS

There was a 100% response rate. Sixteen publicly funded chronic pain management services were identified. There are 27 chronic pain management consultants (16.6 whole time equivalents (WTE)) practicing chronic pain management, amounting to 0.55 specialists (0.34 WTEs)/100,000 of the population. There are 21 WTE for non-consultant hospital doctors (NCHDs), 26.5 WTEs for nursing, 8 WTEs for physiotherapy and 6.2 WTEs for psychology, nationally. A percentage of 93.75% of departments (n = 15) provide interventional therapies, 37.5% (n = 6) provide advanced neuromodulation and 43.75% (n = 7) are managing intrathecal pump therapies. There are five pain management programmes nationally. As of January 2020, ~ 25% patients on waiting lists for outpatient appointments were waiting > 18 months, with ~ 17% patients on waiting lists for interventional treatments waiting > 12 months.

CONCLUSIONS

Shortage of multidisciplinary staff is of particular concern for Irish services. Patient access is limited as evidenced by significant waiting lists. In order to improve access to care and bring services in line with international recommendations, increased resources are needed.

A 4/8 Subtype α-Conotoxin Vt1.27 Inhibits N-Type Calcium Channels With Potent Anti-Allodynic Effect

A novel 4/8 subtype α-conotoxin, Vt1.27 (NCCMFHTCPIDYSRFNC-NH₂), was identified from Conus vitulinus in the South China Sea by RACE methods. The peptide was synthesized and structurally characterized. Similar to other α-conotoxins that target neuronal nicotinic acetylcholine receptor (nAChR) subtypes, Vt1.27 inhibited the rat α3β2 nAChR subtype (IC₅₀ = 1160 nM) and was inactive at voltage-gated sodium and potassium channels in rat sensory neurons. However, Vt1.27 inhibited high voltage-activated N-type (Ca_V2.2) calcium channels expressed in HEK293T cells with an IC₅₀ of 398 nM. An alanine scan of the peptide showed that residues Phe⁵, Pro⁹, Ile¹⁰, and Ser¹³ contribute significantly to the inhibitory activity of Vt1.27. The molecular dockings indicate that Vt1.27 inhibits the transmembrane region of Ca_V2.2, which is different from that of ω-conotoxins. Furthermore, Vt1.27 exhibited potent anti-allodynic effect in rat partial sciatic nerve injury (PNL) and chronic constriction injury (CCI) pain models at 10 nmol/kg level with the intramuscular injection. The pain threshold elevation of Vt1.27 groups was higher than that of α-conotoxin Vc1.1 in CCI rat models. These findings expand our knowledge of targets of α-conotoxins and potentially provide a potent, anti-allodynic peptide for the treatment of neuropathic pain.

Pain Management Strategies After Orthopaedic Trauma: A Mixed-Methods Study with a View to Optimizing Practices

PURPOSE

To examine 1) pain management strategies within the care trajectory of orthopaedic trauma patients and patients' perception of their effectiveness, 2) adverse effects (AEs) associated with pharmacological treatments, particularly opioids and cannabis, and 3) patients' perceptions of strategies that should be applied after an orthopaedic trauma and support that they should obtain from health professionals for their use.

PATIENTS AND METHODS

This study was conducted with orthopaedic trauma patients in a level 1 trauma center. A convergent mixed-methods design was used. Data on pain experience, pain management strategies used and AEs were collected with self-administered questionnaires at hospital discharge (T1) and at 3 months after injury (T2). Patients' preferences about the pain management strategies used, the required support and AEs were further examined through semi-structured individual interviews at the same time measures. Descriptive statistics and thematic analyses were performed.

RESULTS

Seventy-one patients were recruited and 30 individual interviews were undertaken. Pharmacological pain management strategies used at T1 and T2 were mainly opioids (95.8%; 20.8%) and acetaminophen (91.5%; 37.5%). The most frequently applied non-pharmacological strategies were sleep (95.6%) and physical positioning (89.7%) at T1 and massage (46.3%) and relaxation (32.5%) at T2. Findings from quantitative and qualitative analyses highlighted that non-pharmacological strategies, such as comfort, massage, distraction, and physical therapy, were perceived as the most effective by participants. Most common AEs related to opioids were dry mouth (78.8%) and fatigue (66.1%) at T1 and insomnia (30.0%) and fatigue (20.0%) at T2. Dry mouth (28.6%) and drowsiness (14.3%) were the most reported AEs by patients using recreational cannabis. An important need for information at hospital discharge and for a personalized follow-up was identified by participants during interviews.

CONCLUSION

Despite its AEs, we found that opioids are still the leading pain management strategy after an orthopaedic trauma and that more efforts are needed to implement non-pharmacological strategies. Cannabis was taken for recreational purposes but patients also used it for pain relief. Support from health professionals is needed to promote the adequate use of these strategies.

Understanding Adoption and Preliminary Effectiveness of a Mobile App for Chronic Pain Management Among US Military Veterans: Pre-Post Mixed Methods Evaluation

Background

The Veterans Health Administration Pain Coach mobile health app was developed to support veterans with chronic pain.

Objective

Our objective was to evaluate early user experiences with the Pain Coach app and preliminary impacts of app use on pain-related outcomes.

Methods

Following a sequential, explanatory, mixed methods design, we mailed surveys to veterans at 2 time points with an outreach program in between and conducted semistructured interviews with a subsample of survey respondents. We analyzed survey data using descriptive statistics among veterans who completed both surveys and examined differences in key outcomes using paired samples t tests. We analyzed semistructured interview data using thematic analysis.

Results

Of 1507 veterans invited and eligible to complete the baseline survey, we received responses from 393 (26.1%). These veterans received our outreach program; 236 (236/393, 60.1%) completed follow-up surveys. We conducted interviews with 10 app users and 10 nonusers. Among survey respondents, 10.2% (24/236) used Pain Coach, and 58% (14/24) reported it was easy to use, though interviews identified various app usability issues. Veterans who used Pain Coach reported greater pain self-efficacy (mean 23.1 vs mean 16.6; P=.01) and lower pain interference (mean 34.6 vs mean 31.8; P=.03) after (vs before) use. The most frequent reason veterans reported for not using the app was that their health care team had not discussed it with them (96/212, 45.3%).

Conclusions

Our findings suggest that future efforts to increase adoption of Pain Coach and other mobile apps among veterans should include health care team endorsement. Our findings regarding the impact of Pain Coach use on outcomes warrant further study.

Evaluation of injectable nucleus augmentation materials for the treatment of intervertebral disc degeneration

Back pain affects a person's health and mobility as well as being associated with large health and social costs. Lower back pain is frequently caused by degeneration of the intervertebral disc. Current operative and non-operative treatments are often ineffective and expensive. Nucleus augmentation is designed to be a minimally invasive method of restoring the disc to its native healthy state by restoring the disc height, and mechanical and/or biological properties. The majority of the candidate materials for nucleus augmentation are injectable hydrogels. In this review, we examine the materials that are currently under investigation for nucleus augmentation, and compare their ability to meet the design requirements for this application. Specifically, the delivery of the material into the disc, the mechanical properties of the material and the biological compatibility are examined. Recommendations for future testing are also made.

High Frequency 10 kHz Spinal Cord Stimulation as a First Line Programming Option for Patients With Chronic Pain: A Retrospective Study and Review of the Current Evidence

Introduction Neuromodulation is an evolving and increasingly popular therapy for chronic pain management. Recent data suggest that novel waveforms have demonstrated greater benefit over traditional spinal cord stimulation (SCS). The authors conducted a retrospective review of patients undergoing high-frequency 10 kHz SCS at a single tertiary medical center for the purpose of contributing further evidence to this growing body of data. The literature of high-frequency SCS published to date was also reviewed. Methods A retrospective chart review was performed for patients with chronic pain syndrome, including failed back surgery syndrome and sciatica alone, who underwent high-frequency SCS at 10 kHz. This data was analyzed using R software (R Foundation for Statistical Computing, Vienna, Austria) for statistical analysis. The PubMed database was searched for relevant articles using the search terms "high frequency," "10 kHz," and "spinal cord stimulation." All relevant studies conducted to date were included in this literature review. Results Twenty-one patients had complete follow-up data and were included in this study. Of the 21 patients, 85.7% subjectively reported post-operative pain relief while 71.4% of the total patients reported pain relief by ≥ 50%. There was a statistically significant decrease in mean VAS scores from pre-operative to 12-months post-operative (8.52 vs 4.37, p < 0.001). Additionally, 76.5% of patients subjectively reported improvements in sleep and activities of daily living. Recent studies indicate that high-frequency SCS appears to be a viable option for delivering quality pain relief in patients for chronic regional pain syndrome, failed back surgery syndrome, sciatica, and also pain in the upper cervical region of the spine. Conclusion This article provides evidence both with the authors' own institutional data and from the currently published literature for the efficacy of using high-frequency SCS at 10 kHz as a first-line programming option for patients undergoing SCS.

Medical cannabis or cannabinoids for chronic non-cancer and cancer related pain: a systematic review and meta-analysis of randomised clinical trials

OBJECTIVE

To determine the benefits and harms of medical cannabis and cannabinoids for chronic pain.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE, EMBASE, AMED, PsycInfo, CENTRAL, CINAHL, PubMed, Web of Science, Cannabis-Med, Epistemonikos, and trial registries up to January 2021.

STUDY SELECTION

Randomised clinical trials of medical cannabis or cannabinoids versus any non-cannabis control for chronic pain at ≥1 month follow-up.

DATA EXTRACTION AND SYNTHESIS

Paired reviewers independently assessed risk of bias and extracted data. We performed random-effects models meta-analyses and used GRADE to assess the certainty of evidence.

RESULTS

A total of 32 trials with 5174 adult patients were included, 29 of which compared medical cannabis or cannabinoids with placebo. Medical cannabis was administered orally (n=30) or topically (n=2). Clinical populations included chronic non-cancer pain (n=28) and cancer related pain (n=4). Length of follow-up ranged from 1 to 5.5 months. Compared with placebo, non-inhaled medical cannabis probably results in a small increase in the proportion of patients experiencing at least the minimally important difference (MID) of 1 cm (on a 10 cm visual analogue scale (VAS)) in pain relief (modelled risk difference (RD) of 10% (95% confidence interval 5% to 15%), based on a weighted mean difference (WMD) of -0.50 cm (95% CI -0.75 to -0.25 cm, moderate certainty)). Medical cannabis taken orally results in a very small improvement in physical functioning (4% modelled RD (0.1% to 8%) for achieving at least the MID of 10 points on the 100-point SF-36 physical functioning scale, WMD of 1.67 points (0.03 to 3.31, high certainty)), and a small improvement in sleep quality (6% modelled RD (2% to 9%) for achieving at least the MID of 1 cm on a 10 cm VAS, WMD of -0.35 cm (-0.55 to -0.14 cm, high certainty)). Medical cannabis taken orally does not improve emotional, role, or social functioning (high certainty). Moderate certainty evidence shows that medical cannabis taken orally probably results in a small increased risk of transient cognitive impairment (RD 2% (0.1% to 6%)), vomiting (RD 3% (0.4% to 6%)), drowsiness (RD 5% (2% to 8%)), impaired attention (RD 3% (1% to 8%)), and nausea (RD 5% (2% to 8%)), but not diarrhoea; while high certainty evidence shows greater increased risk of dizziness (RD 9% (5% to 14%)) for trials with <3 months follow-up versus RD 28% (18% to 43%) for trials with ≥3 months follow-up; interaction test P=0.003; moderate credibility of subgroup effect).

CONCLUSIONS

Moderate to high certainty evidence shows that non-inhaled medical cannabis or cannabinoids results in a small to very small improvement in pain relief, physical functioning, and sleep quality among patients with chronic pain, along with several transient adverse side effects, compared with placebo. The accompanying BMJ Rapid Recommendation provides contextualised guidance based on this body of evidence. SYSTEMATIC REVIEW REGISTRATION: https://osf.io/3pwn2.

Cognitive Change and Relaxation as Key Mechanisms of Treatment Outcome in Chronic Pain: Evidence From Routine Care

Despite effective treatment approaches within the cognitive behavioral framework general treatment effects for chronic pain are rather small to very small. Translation from efficacy trials to naturalistic settings is questionable. There is an urgent need to improve the effectiveness of well-established treatments, such as cognitive-behavior therapy (CBT) and the investigation of mechanisms of change is a promising opportunity. We performed secondary data analysis from routine data of 1,440 chronic pain patients. Patients received CBT in a multidisciplinary setting in two inpatient clinics. Effect sizes and reliable change indices were computed for pain-related disability and depression. The associations between changes in the use of different pain coping skills (cognitive restructuring, activity despite pain, relaxation techniques and mental distraction) and changes in clinical outcomes were analyzed in structural equation models. Pre-post effect sizes range from g = 0.47 (disability) to g = 0.89 (depression). Changes in the use of cognitive restructuring, relaxation and to a lesser degree mental distraction were associated with changes in disability and depression. Effects from randomized trials can be translated to naturalistic settings. The results complement experimental research on mechanisms of change in the treatment of chronic pain and indicate an important role of cognitive change and relaxation as mechanisms of change. Our findings cautiously suggest that clinicians should optimize these processes in chronic pain patients to reduce their physical and emotional disability.

Analgesic Effect of Combined Therapy with the Japanese Herbal Medicine "Yokukansan" and Electroacupuncture in Rats with Acute Inflammatory Pain

Background: Japanese herbal medicine, called Kampo medicine, and acupuncture are mainly used in Japanese traditional medicine. In this experiment, the analgesic effect of Yokukansan (YKS) alone and a combination of YKS and electroacupuncture (EA) on inflammatory pain induced by formalin injection were examined. Methods: Animals were divided into four groups: a control group, formalin injection group (formalin), YKS-treated formalin group (YKS), and YKS- and EA-treated formalin group (YKS + EA). The duration of pain-related behaviors and extracellular signal-regulated protein kinase (ERK) activation in the spinal cord after formalin injection in the right hind paw were determined. Results: The duration of pain-related behaviors was dramatically prolonged in the late phase (10–60 min) in the formalin group. The YKS treatment tended to reduce (p = 0.08), whereas YKS + EA significantly suppressed the pain-related behaviors (p < 0.01). Immunohistochemical and Western blot analyses revealed that the number of phosphorylated ERK1/2 (pERK1/2)-positive cells and the pERK expression level, which were increased by formalin injection, were significantly inhibited by YKS (p < 0.05) and YKS + EA (p < 0.01). Conclusions: The YKS + EA combination therapy elicited an analgesic effect on formalin-induced acute inflammatory pain.

Health-related guilt in chronic primary pain: A systematic review of evidence

PURPOSE

Chronic primary pain conditions are characterized by significant functional disability, emotional distress, and diagnostic uncertainty. Health-related guilt associated with coping and living with chronic pain is poorly understood. There had been no attempts to synthesize findings on health-related guilt across studies. Therefore, the aim of this study was to conduct a systemic review of evidence, to enable an understanding of the role of health-related guilt in chronic primary pain, and to provide directions for future research.

METHOD

A search strategy was developed based on our eligibility criteria. Four databases (PsycINFO, Scopus, PubMed, and Web of Science) were searched for relevant papers from inception to 8 July 2020. Data from 12 qualitative and six quantitative studies were synthesized narratively.

RESULTS

The review of qualitative studies resulted in three themes, relating to the management of pain, diagnostic uncertainty/legitimizing pain, and how participants' actions or inactions affect others. These findings were integrated with evidence from quantitative studies, which showed that higher levels of guilt were associated with more pain and pain interference, functional impairment, and poorer psychological and social functioning.

CONCLUSIONS

The findings demonstrate that health-related guilt is an important psychological factor associated with more pain and poorer function in people with chronic primary pain conditions. Future research should examine health-related guilt as a potential mediating/moderating factor leading to more distress and suffering in this population and as a potential target for interventions.

Animal models of pain: Diversity and benefits

Chronic pain is a maladaptive neurological disease that remains a major health problem. A deepening of our knowledge on mechanisms that cause pain is a prerequisite to developing novel treatments. A large variety of animal models of pain has been developed that recapitulate the diverse symptoms of different pain pathologies. These models reproduce different pain phenotypes and remain necessary to examine the multidimensional aspects of pain and understand the cellular and molecular basis underlying pain conditions. In this review, we propose an overview of animal models, from simple organisms to rodents and non-human primates and the specific traits of pain pathologies they model. We present the main behavioral tests for assessing pain and investing the underpinning mechanisms of chronic pathological pain. The validity of animal models is analysed based on their ability to mimic human clinical diseases and to predict treatment outcomes. Refine characterization of pathological phenotypes also requires to consider pain globally using specific procedures dedicated to study emotional comorbidities of pain. We discuss the limitations of pain models when research findings fail to be translated from animal models to human clinics. But we also point to some recent successes in analgesic drug development that highlight strategies for improving the predictive validity of animal models of pain. Finally, we emphasize the importance of using assortments of preclinical pain models to identify pain subtype mechanisms, and to foster the development of better analgesics.

Emotional affection on a sustained attention task: The importance the aging process and depression

Chronic pain is a complex experience that has now become a major public health issue. This has prompted many researchers to study attention, understanding it to be a crucial factor that allows altering the experience of pain, while attributing considerable importance to sustained attention. Accordingly, the main studies in this field stress the importance of emotion regulation processes and emotions on the perception of painful stimuli and attentional processes themselves. Nevertheless, only a handful of studies have been found that directly study the relationship between these variables. Within this context, this article sets out to analyse emotional regulation processes, emotional variables (depression and anxiety), the experience of pain, and age on the ability to maintain the vigilance response in a sample of patients with chronic pain. This involved selecting a sample of 49 patients with rheumatoid arthritis and examining their performance in an ad-hoc sustained attention test. With a view to complying with the study's main purpose, the participants were also assessed through the use of the following self-report measures: the Beck Depression Inventory (BDI-I); the Hospital Anxiety and Depression Scale (HADS); the McGill Pain Questionnaire, and the Difficulties in Emotion Regulation Scale (DERS). Linear regression analyses revealed a significant impact of the aging process on the performance times in the attention task. Likewise, age and depression recorded a significant correlation with the mistakes made during the task. These results suggest that higher depression levels and an older age might be related to a worse adaptation to pain management techniques based on attention processes, such as mindfulness.

The ceramide-S1P pathway as a druggable target to alleviate peripheral neuropathic pain

Introduction: Neuropathic pain disorders are diverse, and the currently available therapies are ineffective in the majority of cases. Therefore, there is a major need for gaining novel mechanistic insights and developing new treatment strategies for neuropathic pain. Areas covered: We performed an in-depth literature search on the molecular mechanisms and systemic importance of the ceramide-to-S1P rheostat regulating neuron function and neuroimmune interactions in the development of neuropathic pain. Expert opinion: The S1P receptor modulator FTY720 (fingolimod, Gilenya®), LPA receptor antagonists and several mechanistically related compounds in clinical development raise great expectations for treating neuropathic pain disorders. Research on S1P receptors, S1P receptor modulators or SPHK inhibitors with distinct selectivity, pharmacokinetics and safety must provide more mechanistic insight into whether they may qualify as useful treatment options for neuropathic pain disorders. The functional relevance of genetic variations within the ceramide-to-S1P rheostat should be explored for an enhanced understanding of neuropathic pain pathogenesis. The ceramide-to-S1P rheostat is emerging as a critically important regulator hub of neuroimmune interactions along the pain pathway, and improved mechanistic insight is required to develop more precise and effective drug treatment options for patients suffering from neuropathic pain disorders.

A Systematic Review of Economic Evaluations Reporting the Cost-Effectiveness of Spinal Cord Stimulation

OBJECTIVES

Spinal cord stimulation (SCS) is a recognized treatment for chronic pain. This systematic review aims to assess economic evaluations of SCS for the management of all chronic pain conditions, summarize key findings, and assess the quality of studies to inform healthcare resource allocation decisions and future research.

METHODS

Economic evaluations were identified by searching general medical and economic databases complemented with screening of reference lists of identified studies. No restrictions on language or treatment comparators were applied. Relevant data were extracted. The quality of included studies was assessed using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist.

RESULTS

Fourteen studies met the inclusion criteria and were judged to be of acceptable quality. Economic evaluations assessed SCS for the management of refractory angina pectoris, failed back surgery syndrome (FBSS), complex regional pain syndrome (CRPS), diabetic peripheral neuropathy (DPN), and peripheral arterial disease. Model-based studies typically applied a 2-stage model, i.e. decision tree followed by Markov model. Time horizon varied from 1 year to lifetime. Cost-effectiveness ranged widely from dominant (SCS cost-saving and more effective) to incremental cost-effectiveness ratio of >£100,000 per quality-adjusted life-year. Cost-effectiveness appeared to depend on the time horizon, choice of comparator, and indication. Ten of the studies indicated SCS as cost-saving or cost-effective compared with the alternative strategies.

CONCLUSION

The results consistently suggest that SCS is cost-effective when considering a long-term time horizon, particularly for the management of FBSS and CRPS. Further studies are needed to assess the cost-effectiveness of SCS for ischemic pain and DPN.

The Impact of Cognitive Anxiety and the Rating of Pain on Care Processes in a Vigilance Task: The Important Part Played by Age

Chronic pain is a serious public health problem that has grown exponentially in recent years, which is why it has received the attention of numerous researchers. Most of the studies in the field of chronic pain have focused on care as a mediating variable on the perception of painful stimuli and emotions. Nevertheless, there are very few studies that have gone in the opposite direction. This study's aim is therefore to analyse the impact of emotional variables (anxiety and depression), the rating of pain, and age on vigilance processes in a sample of patients with chronic pain. To do so, the attentional performance of a cohort of 52 patients with chronic pain was measured through the use of a modified dot-probe task. Furthermore, all the participants were evaluated using the following self-report measures: Beck's Depression Inventory-II (BDI-II), the McGill Pain Questionnaire, and the Pain Anxiety Symptoms Scale-20 (PASS-20). Stepwise multiple linear regression analysis revealed a significant negative correlation between the pain rating index and the number of mistakes the participants made during the attention test. There was also a positive and significant correlation with age and another negative and significant correlation with cognitive anxiety regarding the overall performance times during the undertaking of the experimental task. These results point to the importance of a more in-depth understanding of the impact that the emotional variables and other variables such as age have on attentional processes and the rating of pain. Finally, the discussion focuses on the implications these results could have for clinical practice or for future research studies in this field.

Anxiety, Reinforcement Sensitivity and Social Context in Accepting the Experience of Pain Among Rheumatoid Arthritis Patients

Background: Acceptance has become one of the most widely studied processes regarding chronic pain because of its ability to influence participants' adaptation and coping responses. Leading researchers have found relationships between variables such as anxiety, reinforcement sensitivity, and the responses of the participants' environment to their behavior and acceptance. In contrast, few studies have been found that investigate the variables that predict the acceptance of pain. This study has set out to explore the relationships between pain-related anxiety, sensitivity to contingencies, and the punishment responses of significant people toward pain behaviors regarding pain acceptance. Methods: With a view to fulfilling this purpose, a cohort of 62 participants with rheumatoid arthritis was chosen, and the subjects were assessed through the following self-report measures: Chronic Pain Acceptance Questionnaire, CPAQ; Pain Anxiety Symptoms Scale, PASS-20; The Sensitivity to Punishment and Sensitivity to Reward Questionnaire, SPSRQ, and The West Haven-Yale Multidimensional Pain Inventory, WHYMPI. The study's initial objectives were achieved by means of a stepwise multiple linear regression analysis. Results: The linear regression analyses revealed a negative and significant correlation between anxiety, reinforcement sensitivity, and the significant persons' responses to pain behaviors and pain acceptance. Conclusion: The results suggest that the identification of these variables might be important for addressing these participants' pain. Finally, the discussion focuses on our findings' implications as regards their use in clinical practice.

Selective local anesthesia versus corticosteroid infiltration on low back pain: a randomized clinical trial

ANTECEDENTS AND OBJECTIVE

Local infiltrations are second line therapy in the treatment of chronic low back pain, although their use is controversial in the literature. Our objective was to compare the effectiveness of 2 types of infiltration at the paravertebral lumbar level in two groups of patients diagnosed with low back pain: corticosteroids, and selective local anaesthetic administered using segmental neural therapy (SNT).

MATERIAL AND METHODS

Double-blind clinical trial in 55 patients diagnosed with low back pain in the neurosurgery department of the Hospital Central de la Defensa Gómez Ulla. Patients were randomised to 2 treatment groups to receive either paravertebral injections of corticosteroids or SNT. Outcomes were measured using a visual analogue scale, the Oswestry Disability Index, the Short Form-36, and patient satisfaction at the start of treatment (baseline) and at 3 and 12 months post intervention.

RESULTS

The combined treatment group showed a statistically significant improvement in Oswestry Disability Index at 3 months. The SNT group showed a statistically significant improvement in baseline visual analogue scale vs. visual analogue scale at 3 (1.398cm, p=0.001) and 12 months (0.791cm, p=0.007). No differences were observed in the remaining variables measured. The percentage of patients that would repeat the treatment was 81% and 83%, respectively.

CONCLUSIONS

Significant pain relief was achieved with SNT, and disability improved with the combined treatment. Although clinical improvement was limited, patients were satisfied. Local infiltrations should be considered as an alternative treatment for chronic low back pain.

CLINICAL TRIAL REGISTRATION

This clinical trial was registered at the European Union Clinical Trials Register with EUDRA-CT number 2015-001146-29.

miR-200a-3p modulates gene expression in comorbid pain and depression: Molecular implication for central sensitization

Chronic pain and depression are often comorbid exhibiting common clinical presentations and biological connections related to central nervous system sensitization. Epigenetic regulation of gene expression in the brain plays a crucial role in response to long-lasting stress and chronic pain, and microRNA imbalance in the prefrontal cortex (PFC) might be involved in central sensitization. Male Sprague Dawley rats were subjected to unpredictable chronic mild stress (UCMS) and spared nerve injury (SNI) to initiate depressive-like behavior and chronic pain behavior, respectively. The next-generation sequencing technique was employed to analyze PFC microRNAs in both the UCMS and SNI models. Rats exposed to either UCMS or SNI exhibited both depressive-like and chronic pain behaviors. Five specific microRNAs (miR-10a-5p, miR-182, miR-200a-3p, miR-200b-3p, and miR-429) were simultaneously down-regulated in the depressive-like and chronic pain models after 4 weeks of short-term stress. Gene ontology revealed that the 4-week period of stress enhanced neurogenesis. Only the miR-200a-3p level was continuously elevated under prolonged stress, suggesting roles of reduced neurogenesis, inflammatory activation, disturbed circadian rhythm, lipid metabolism, and insulin secretion in the co-existence of pain and depression. Thus we conclude that miR-200a-3p might be a specific biomarker of central sensitization in chronic pain and depression.

Reduction mammoplasty and back pain: a systematic review and meta-analysis

Purpose

There is anecdotal evidence that many patients who undergo reduction mammoplasty (RM) procedures, to relieve symptoms of large breasts, also report improvement in existing back pain. Given how important back pain is as a healthcare burden, the literature which explores the relationship between RM and back pain is sparse. Thus, we aimed to appraise whether such a correlation exists, through systematic review and meta-analysis.

Method

Adhering to PRISMA methodology, we used the OVID engine to search the MEDLINE and Embase databases with predefined search terms and inclusion criteria. MeSH terms were not exploded. Statistical analysis was performed using Review Manager 5.3, employing a Mantell–Haenszel method and a fixed-effect model suitable for dichotomous data.

Results

The review yielded 13 articles after exclusions, eight of which were suitable for quantitative analysis. The results of the analysis suggested an improvement in back pain following RM across all studies (OR 40.37 [8.09, 201.53] 95% CI, n = 1008). Heterogeneity was high (τ2 = 5.14, χ2 = 230.37, df = 7 (p < 0.00001) i2 = 97%).

Conclusions

Although cursory, the evidence gleaned suggests that RM reduces the prevalence of back pain in patients with large breasts. Furthermore, we highlight the scarcity of studies investigating whether RM is at the clinical threshold of efficacy in treating back pain. Although the evidence is insufficient for recommending RM as a management option aimed at treating back pain, this review does identify the need for prospective data looking at back pain metrics as a specific outcome measure before and after reduction mammoplasty.

Graphic abstract

A guided and unguided internet- and mobile-based intervention for chronic pain: health economic evaluation alongside a randomised controlled trial

OBJECTIVE

This study aims at evaluating the cost-effectiveness and cost-utility of a guided and unguided internet-based intervention for chronic pain patients (ACTonPain_guided and ACTonPain_unguided) compared with a waitlist control group (CG) as well as the comparative cost-effectiveness of the guided and the unguided version.

DESIGN

This is a health economic evaluation alongside a three-arm randomised controlled trial from a societal perspective. Assessments were conducted at baseline, 9 weeks and 6 months after randomisation.

SETTING

Participants were recruited through online and offline strategies and in collaboration with a health insurance company.

PARTICIPANTS

302 adults (≥18 years, pain for at least 6 months) were randomly allocated to one of the three groups (ACTonPain_guided, ACTonPain_unguided, CG).

INTERVENTIONS

ACTonPain consists of seven modules and is based on Acceptance and Commitment Therapy. ACTonPain_guided and ACTonPain_unguided only differ in provision of human support.

PRIMARY AND SECONDARY OUTCOME MEASURES

Main outcomes of the cost-effectiveness and the cost-utility analyses were meaningful change in pain interference (treatment response) and quality-adjusted life years (QALYs), respectively. Economic evaluation estimates were the incremental cost-effectiveness and cost-utility ratio (ICER/ICUR).

RESULTS

At 6-month follow-up, treatment response and QALYs were highest in ACTonPain_guided (44% and 0.280; mean costs = €6,945), followed by ACTonPain_unguided (28% and 0.266; mean costs = €6,560) and the CG (16% and 0.244; mean costs = €6,908). ACTonPain_guided vs CG revealed an ICER of €45 and an ICUR of €604.ACTonPain_unguided dominated CG. At a willingness-to-pay of €0 the probability of being cost-effective was 50% for ACTonPain_guided (vs CG, for both treatment response and QALY gained) and 67% for ACTonPain_unguided (vs CG, for both treatment response and QALY gained). These probabilities rose to 95% when society's willingness-to-pay is €91,000 (ACTonPain_guided) and €127,000 (ACTonPain_unguided) per QALY gained. ACTonPain_guided vs ACTonPain_unguided revealed an ICER of €2,374 and an ICUR of €45,993.

CONCLUSIONS

Depending on society's willingness-to-pay, ACTonPain is a potentially cost-effective adjunct to established pain treatment. ACTonPain_unguided (vs CG) revealed lower costs at better health outcomes. However, uncertainty has to be considered. Direct comparison of the two interventions does not indicate a preference for ACTonPain_guided.

TRIAL REGISTRATION NUMBER

DRKS00006183.

The societal costs of chronic pain and its determinants: The case of Austria

BACKGROUND

Chronic pain is among the most burdensome conditions. Its prevalence ranges between 12% and 30% in Europe, with an estimated 21% among Austrian adults. The economic impact of chronic pain from a societal perspective, however, has not been sufficiently researched. This study aims to provide an estimate of the societal costs for working-age adults with chronic pain in Austria. It explores the impact of sex, number of pain sites, self-reported pain severity, health literacy and private health insurance on costs associated with chronic pain.

METHODS

A bottom-up cost-of-illness study was conducted based on data collected from 54 adult patients with chronic pain at three Viennese hospital outpatient departments. Information on healthcare costs including out-of-pocket expenses and productivity losses due to absenteeism and informal care were collected over 12 months. Resource use estimates were combined with unit costs and mean costs per patient were calculated in € for year 2016.

RESULTS

Mean annual societal costs were estimated at EUR 10191. Direct medical costs were EUR 5725 including EUR 1799 out-of-pocket expenses (mainly pain relieving activities and private therapy). Productivity losses including informal care amounted to EUR 4466. Total costs for women and patients with three or more pain sites were significantly higher. No association with health literacy was found but there was a tendency towards higher out-of-pocket expenses for patients with complementary private health insurance.

CONCLUSION

This study is the first to provide a comprehensive assessment of the individual and societal burden of chronic pain in Austria. It highlights that chronic pain is associated with substantial direct medical costs and productivity losses. Patient costs may show systematic differences by health insurance status, implying a need for future research in this area.

Chalcone derivatives: synthesis, in vitro and in vivo evaluation of their anti-anxiety, anti-depression and analgesic effects

Anxiety disorders, depression and pain are highly prevalent pathologies. Their pharmacotherapy is associated with unwanted side effects; hence there is a clinical need to develop more effective drugs with fewer adverse reactions.

Chalcones are one of the major classes of naturally occurring compounds. Chalcones and their derivatives have a huge importance in medicinal chemistry, displaying a wide range of pharmacological activities including anti-inflammatory, antimicrobial, antioxidant, cytotoxic and antitumor actions.

The aim of this work was to evaluate chalcone effects on different targets involved in these pathologies. We have synthesized a series of simple chalcone derivatives taking common structural requirements described in literature related to their anxiolytic-like, antidepressant-like and/or antinociceptive properties into account.

Furthermore, their potential in vitro effects towards different targets involved in these pathologies were evaluated. We have obtained twenty chalcones with moderate to high yields and assessed their ability to bind distinctive receptors, from rat brain homogenates, by displacement of labelled specific ligands: [³H] FNZ (binding site of benzodiazepines/GABA_A), [³H] 8-OH-DPAT (serotonin 5-HT_1A) and [³H] DAMGO (μ-opioid). Those compounds that showed the better in vitro activities were evaluated in mice using different behavioural tasks. In vivo results showed that 5′-methyl-2′-hydroxychalcone (9) exerted anxiolytic-like effects in mice in the plus maze test. While chalcone nuclei (1) revealed antidepressant-like activities in the tail suspension test. In addition, the novel 5′-methyl-2′-hydroxy-3′-nitrochalcone (12) exhibited antinociceptive activity in acute chemical and thermal nociception tests (writhing and hot plate tests). In conclusion, chalcones are thus promising compounds for the development of novel drugs with central nervous system (CNS) actions.

The Benzimidazole Derivatives, B1 (N-[(1H-Benzimidazol-2-yl)Methyl]-4-Methoxyaniline) and B8 (N-{4-[(1H-Benzimidazol-2-yl)Methoxy]Phenyl}Acetamide) Attenuate Morphine-Induced Paradoxical Pain in Mice

Despite being routinely used for pain management, opioid use is limited due to adverse effects such as development of tolerance and paradoxical pain, including thermal hyperalgesia and mechanical allodynia. Evidence indicates that continued morphine administration causes increased expression of proinflammatory mediators such as tumor necrosis factor-alpha (TNF-α). The objectives of the present study were to determine the effects of B1 (N-[(1H-benzimidazol-2-yl)methyl]-4-methoxyaniline) and B8 (N-{4-[(1H-benzimidazol-2-yl)methoxy]phenyl}acetamide), benzimidazole derivatives, on thermal nociception and mechanical allodynia during repeated morphine (intraperitoneal; 5 mg/kg twice daily for 6 days)-induced paradoxical pain and TNF-α expression in the spinal cord in mice. Our data indicate that administration of benzimidazole derivatives attenuated morphine-induced thermal hyperalgesia and mechanical allodynia. Benzimidazole derivatives also reduced TNF-α expression in mice. Taken together, these results suggest that benzimidazole derivatives might be useful for the treatment of neuroinflammatory consequences of continued morphine administration and could be potential drug candidates for the management of opioid-induced paradoxical pain.

Genetic variants in COL11A2 of lumbar disk degeneration among Chinese Han population

BACKGROUND

Lumbar disk disease (LDD) is a common musculoskeletal disorder. Several predisposing genetic and environmental risk factors have been established for symptomatic LDD.

METHODS

We conducted a case-control association study to investigate the role of the COL11A2 gene in LDD. Genotyping of 384 Chinese Han LDD patients and 384 Chinese Han controls was made for six single-nucleotide polymorphisms (SNPs) from COL11A2 by Agena Massarray. We evaluated these SNPs association with LDD using the chi-square test and genetic model analysis.

RESULTS

The strongest associations with LDD were observed for polymorphisms in rs2071025. Carriers of "A" allele had an increased risk of LDD (OR = 1.47, 95% CI = 1.20-1.80, p = 0.0002) as compared with the "G" allele in allele model. We found that rs2071025 were associated with LDD in female and male from the stratification analyses (p < 0.05). Genetic models showed that rs986522(C) significantly increased the risk of LDD in female; however, in males, we did not find significant associations between the rs986522 and LDD risk.

CONCLUSION

This study showed a genetic association with COL11A2 polymorphism in individuals with LDD. These data may provide novel insights into the pathogenesis of LDD, although further studies with larger numbers of participants worldwide are needed for validation of our conclusions.