Chronic pain as a symptom or a disease: the IASP Classification of Chronic Pain for the International Classification of Diseases (ICD-11)

Chronic pain-induced functional and structural alterations in the brain: A multi-modal meta-analysis

Chronic pain is a debilitating condition associated with brain alterations. However, the variability in neuroimaging results across modalities necessitates a comprehensive multi-modal meta-analysis for a cohesive understanding. This study aims to elucidate brain alterations in chronic pain patients using a multi-modal meta-analysis approach encompassing structural, resting-state functional connectivity, and pain processing paradigms in functional magnetic resonance imaging. A systematic literature search was conducted across PubMed, OVID Embase, OVID Medline, and Web of Science, encompassing studies published up to May 2022, to identify relevant research articles on chronic pain and MRI techniques in three modalities. Inclusion criteria encompassed experiments reporting three modality brain alterations in chronic pain patients, with sufficient statistical thresholds and enough sample size. We conducted voxel-wise meta-analyses using seed-based d mapping to identify significant alterations in each modality. Additionally, conjunction analyses were executed to identify common alterations across these modalities. Ultimately, 47 structure studies, 37 resting state functional connectivity studies, and 41 pain-processing studies were selected for formal analysis. Chronic pain patients displayed notable structural and functional alterations in the insular cortex, characterized by reduced gray matter, disruptions in functional connectivity with the frontoparietal network, and enhanced activation during painful stimuli processing. Distinct activation patterns were observed in the left and right insular cortex for pain stimulus processing versus anticipation. Furthermore, the superior temporal gyrus and superior frontal gyrus exhibited joint alterations across modalities. This multi-modal meta-analysis reveals consistent brain alterations in chronic pain patients, shedding light on the complex interplay between structural and functional changes. PERSPECTIVE: This multi-modal meta-analysis integrates findings from structural, resting-state functional connectivity, and pain processing paradigms in fMRI, revealing consistent brain alterations in chronic pain patients. Notable brain changes highlight the intricate interplay between structural and functional brain changes, advancing our understanding of chronic pain's neural underpinnings.

Understanding the Pain Experience and Treatment Considerations Along the Spectrum of Peripheral Artery Disease: A Scientific Statement From the American Heart Association

Peripheral artery disease (PAD) is an atherosclerotic condition that affects a growing number of individuals worldwide, with estimates exceeding 220 million. One of the central hallmarks of PAD is lower extremity pain, which may present as intermittent claudication and atypical leg pain, and, in more severe cases, ischemic rest pain, neuropathic pain, or phantom limb pain in those who underwent amputation. Although the majority of individuals with PAD may experience pain that is chronic in nature, the pathogenesis and phenomenology of pain may differ. Nociceptive, inflammatory, and neuropathic mechanisms all play a role in the generation of pain. Pain in PAD results in severe disability and can copresent with distress, sickness behaviors such as avoidance and further deconditioning, and concomitant depression, anxiety, and addiction secondary to opioid use. These factors potentially lead to chronic pain interacting with a multitude of domains of functioning, including physical, emotional, and behavioral. Whereas pain is a normal adaptive response, self-defeating behaviors and cognitions contribute to the persistence or worsening of the chronic pain experience, disability, and distress. Much remains unknown about the phenomenology of pain in PAD and its clinical subgroups and how it affects outcomes. Borrowing from other chronic pain syndromes, multimodal pain management strategies that emphasize a biopsychosocial model have generated a solid evidence base for the use of cognitive behavioral approaches to manage pain. Multimodal pain management in PAD is not the norm, but theoretical pathways and road maps for further research, assessment, and clinical implementation are presented in this scientific statement.

Medical expenditures associated with abdominal and pelvic pain in the United States, 2017-2021

Abdominal and pelvic pain are common symptoms prompting medical care, yet little is known about their associated medical expenditures in the U.S. This study estimated the overall and age-specific incremental medical expenditures associated with abdominal and pelvic pain, and compared if the incremental expenditures differ by sex and presence of comorbid overlapping pain conditions. Using data from the 2017-2021 Medical Expenditure Panel Surveys (MEPS), a nationally representative cross-sectional survey on medical expenditures in the U.S., we estimated the incremental medical expenditures associated with abdominal and pelvic pain (ICD-10 indexed) for children (6-17 years), adults (18-64 years), and older adults (65-85 years), controlling for Andersen Behavioral Model factors. In our sample, 1.2% (1779/135,983) were classified with abdominal or pelvic pain. Adjusted incremental expenditures for abdominal and pelvic pain were $4325 (95% CI: $2670-$5981) per person, totaling $16.0 billion annually. Incremental expenditures were $1465 for children, $3439 for adults, and $9301 for older adults. In children, incremental expenditures were concentrated on office-based, outpatient, and emergency department visits. In adults, incremental expenditures were concentrated on office-based, outpatient, emergency department visits, and inpatient admissions. The estimated incremental medical expenditures were higher in males across all age groups. In individuals with abdominal or pelvic pain, comorbid pain conditions were associated with much higher additional incremental medical expenditures across all age groups ($6790 in children, $5262 in adults, and $6040 in older adults). Abdominal and pelvic pain substantially increased medical expenditures for children and adults, especially for those with comorbid overlapping pain conditions. PERSPECTIVE: Our nationwide study quantified the economic burden of abdominal and pelvic pain in the U.S., identifying key demographic and clinical cost drivers. Findings highlight the significant lifetime burden, the importance of pain management, the need to reduce costs for patients with overlapping pain, and the necessity of ongoing cost surveillance.

Chronic pain in multiple sites is associated with depressive symptoms in US adults: A cross-sectional study

BACKGROUND

Chronic pain poses a significant public health challenge, yet its manifestation in multiple body areas remains insufficiently studied. This study seeks to explore the relationship between chronic pain affecting multiple sites and depression.

METHODS

We analyzed data from the National Health and Nutrition Examination Survey (NHANES) from 2009 to 2010 regarding chronic pain and depression, employing weighted univariate and multivariate logistic regression analyses to explore the relationship between the number of body sites impacted by chronic pain and depression rates. Furthermore, subgroup analyses were performed to identify possible confounding factors that could affect this relationship.

RESULTS

There is a correlation between chronic pain and higher risk of depression (OR 3.821, 95% CI 3.138-4.646, P < 0.001). The multivariable-adjusted observational study indicates that, compared to individuals without chronic pain, the risk of depression is significantly associated with an increasing number of body sites affected by chronic pain. Specifically, when a person experiences chronic pain in five different areas, the risk of depression peaks (OR 16.050, 95% CI 8.723-29.905, P < 0.001).

CONCLUSION

The findings of this study indicate a significant correlation between chronic pain in multiple sites and depressive symptoms.

Characterisation of periorbital mechanical allodynia in the reserpine-induced fibromyalgia model in mice: The role of the Schwann cell TRPA1/NOX1 signalling pathway

Fibromyalgia (FM) is a complex and multifaceted condition characterized by a range of clinical symptoms, including widespread pain and a strong association with migraine headaches. Recent findings have underscored the role of oxidative stress and transient receptor potential ankyrin 1 (TRPA1) channel in migraine and FM. However, the precise mechanisms underlying the comorbidity between migraine and FM are unclear. Periorbital mechanical allodynia (PMA), which recapitulates one of the major symptoms of migraine, and the feed-forward mechanism driven by reactive oxygen species and TRPA1, were investigated in a reserpine-induced FM model in C57BL/6J mice, employing pharmacological interventions and genetic approaches. Reserpine-treated mice developed PMA (which was alleviated by antimigraine drugs) and increased endoneurial macrophages and oxidative stress markers in the trigeminal nerve tissues (neuroinflammation). These responses were absent upon macrophage depletion and by pharmacological inhibition or global genetic deletion of the TRPA1 channel. Furthermore, selective silencing of TRPA1 in Schwann cells attenuated both reserpine-induced PMA and neuroinflammation, while selective silencing of TRPA1 in sensory neurons reduced PMA but not neuroinflammation. In reserpine-treated mice, Schwann cell TRPA1 promoted NADPH oxidase 1-mediated reactive oxygen species generation and macrophage density increase in the mouse trigeminal nerve, which sustains PMA. Targeting TRPA1 channels in Schwann cells could offer a novel therapeutic strategy for FM-related headaches.

Associations between endogenous sex hormones and multisite chronic musculoskeletal pain

BACKGROUND

Sex-differences in pain perception have been documented; however, the role of sex hormones in chronic musculoskeletal pain (CMP) remains unclear. Therefore, this study investigated whether sex hormones and sex hormone-binding globulin (SHBG) are associated with CMP.

METHODS

We utilised data from the UK Biobank (n=357 424; females: 51.6%; white: 95.2%). Serum concentrations of oestradiol (E2), testosterone (T), and SHBG were measured at baseline. Chronic pain (≥3 months) in the neck/shoulder, back, hip, knee, or 'all over the body' was assessed at baseline and three follow-ups. Mixed-effects multinomial/logistic regression models were used.

RESULTS

In multivariable analyses, greater concentrations of T and T/SHBG were associated with a lower number of CMP sites in both males (T: relative risk ratio=0.81 per standard deviation, 95% confidence interval [0.77-0.86] and T/SHBG: 0.85 [0.80-0.92]) and females (T: 0.85 [0.81-0.89] and T/SHBG: 0.93 [0.89-0.97] [all P-values for trend ≤0.001]). Greater T concentrations and T/SHBG were also associated with lower odds of CMP across all sites, while higher concentrations of SHBG were associated with lower odds of neck/shoulder CMP in both sexes. There was no association between concentrations of E2, SHBG, or E2/SHBG and number of CMP or site-specific CMP in either sex.

CONCLUSION

In both sexes, greater T concentrations and T/SHBG were associated with lower number of CMP sites and site-specific CMP, while greater concentrations of SHBG were linked to lower odds of neck/shoulder CMP. These findings suggest a potential involvement of sex steroids in the pathogenesis of CMP and underscore the need for further investigation into their potential in chronic pain management strategies.

The properties of TREM1 and its emerging role in pain-related diseases

The TREM1 receptor, a member of the TREMs family, is expressed by myeloid cells and functions as an initiator or enhancer of the inflammatory response, playing a pivotal role in the regulation of inflammation. In recent years, it has been found that TREM1-mediated inflammatory response is involved in the regulation of pain-related diseases. This article provides an extensive review on the structural characteristics and distribution patterns, ligand, signaling pathways, inhibitors, and pathophysiological roles of TREM1 in pain disorders aiming to further elucidate its biological function and offer novel insights for clinical interventions targeting pain-related diseases.

Innovative therapeutic strategies using ADHD medications tailored to the behavioral characteristics of patients with chronic pain

Chronic pain affects a significant portion of adults and is linked to psychosocial issues, cognitive dysfunction, and psychiatric disorders, complicating treatment. Attention deficit hyperactivity disorder (ADHD) is increasingly recognized as a contributing factor to chronic pain, particularly nociplastic pain, with a notable prevalence of comorbidity between ADHD and conditions like fibromyalgia and chronic low back pain. ADHD behaviors such as impulsivity and overactivity can exacerbate pain by leading patients to seek risky treatments or discontinue care prematurely. ADHD medications are expected to alleviate pain severity by improving associated cognitive dysfunction and addressing central sensitization, a fundamental mechanism in chronic pain. Brain abnormalities in ADHD contribute to increased spontaneous activity in the anterior cingulate cortex-posterior insular pathway due to neuroinflammation, alterations in action potential firing, and changes in transmission pathways in the spinal dorsal horn. Additionally, increased norepinephrine synthesis and reduced transmission efficiency amplify nociceptive information from the periphery and facilitate central sensitization in ADHD. Beyond typical ADHD medications like central stimulants, norepinephrine reuptake inhibitors, and alpha-2 receptor agonists, various antidepressants, mood stabilizers, antipsychotics, Parkinson's disease medications, and antidementia medications have proven effective in alleviating ADHD symptoms. These medications, effective for ADHD, may offer innovative solutions for managing chronic pain by targeting both the cognitive/behavioral dysfunction and central sensitization observed in chronic pain comorbid with ADHD. Further research into these mechanisms could lead to new, more effective pharmacological treatments for chronic pain with comorbid ADHD, a condition that is often overlooked.

The association of chronic pain, painkiller use, and potential mediators with liver fat content

Excessive accumulation of liver fat content (LFC) is a pathological manifestation of steatotic liver diseases. This study aims to investigate the relationship between chronic pain and LFC development. In the UK Biobank, chronic pain sites were collected via questionnaire, while LFC was measured by magnetic resonance imaging and quantified by Proton Density Fat Fraction (PDFF). During the median follow-up of 10.5 (4.0-17.8) years, in 39,437 individuals, neck/shoulder, back, stomach/abdominal, knee, and general pain achieved significant arithmetic means difference of 0.02, 0.02, 0.04, 0.02, and 0.15 in PDFF (P < 0.05) using multivariable linear regression models. There was a significant dose-effect for number of pain sites and PDFF (P < 0.001). Additionally, the link between pain sites and PDFF was much stronger in aspirin users than non-users, while steroids had the reverse effect (P for interaction < 0.05). C-reactive protein, sleep, diet, and depression were proved to mediated 8.41%, 13.3%, 6.6%, and 23.0% of the relationship, respectively. In conclusion, there were quantified differences in the relationship between chronic pain and LFC. For chronic pain patients with potential liver health issues, aspirin may be prioritized as an analgesic option due to its potential protective benefits, whereas steroid medications should be avoided.

Comparative analysis of acute and chronic painful temporomandibular disorders: Insights into pain, behavioral, and psychosocial features

OBJECTIVE

The scarcity of literature necessitates further research to differentiate between acute and chronic painful temporomandibular disorders (TMDs). This study compared pain characteristics, oral behaviors, jaw function, and psychosocial distress between TMD patients with acute and chronic pain, examined correlations among variables, and identified factors associated with chronic pain-related TMDs (PT).

METHODS

Anonymized data were gathered from consecutive patients seeking TMD treatment at a university-based oral medicine clinic. Axis I diagnoses were made using the Diagnostic Criteria for TMDs, and patients with PT were categorized into acute (AP) and chronic pain (CP) groups. Axis II assessments were performed, evaluating pain characteristics, oral behaviors, jaw functional limitation, somatic symptoms, depression, and anxiety. Statistical analysis utilized chi-square/non-parametric tests and logistic regression (α =  0.05).

RESULTS

Among the 488 PT patients, 34.6% experienced AP and 65.4% had CP. Significant differences were observed in pain intensity, interference, disability, jaw overuse behavior, functional limitation, somatic symptom burden, depression, and anxiety. (CP>  AP). Moderate-to-strong correlations were found in both the AP (rs =  0.43-0.83) and CP (rs =  0.46-0.87) groups, although the specific relationships between pain, behavioral, and psychosocial factors differed somewhat. The multivariate regression model revealed that only pain intensity (OR =  1.01) and oral behaviors (OR =  1.06) significantly increased the odds of chronic PT.

CONCLUSION

Chronic pain was more prevalent in PT patients and associated with greater severity in pain, behavioral, and psychosocial variables. Pain intensity and oral behaviors were linked to an increased likelihood of chronic pain.

Neuropathic Symptoms and Frequency of Chronic Pain in an International Online Sample of Individuals with Sub-Acute and Chronic Stroke

Background/Objectives: Chronic pain is common following a stroke and is associated with increased disability. Yet, little is known about the chronic pain experience in the stroke population. This study aimed to identify and explore the features and neuropathic symptoms of chronic pain in individuals with longstanding stroke. Methods: This observational study utilized an online survey that was developed for individuals who have had a stroke (>3 months). Data sought included participant demographics, medical history, and details of the stroke(s). Participants who reported experiencing chronic pain completed the Numerical Rating Scale for Pain, the Neuropathic Pain Symptom Inventory, and body maps to indicate region(s) of pain. Results: A total of 533 individuals with longstanding stroke participated. Chronic pain was reported as being experienced by 60% of participants and was more frequently experienced by individuals who reported being female (p = 0.002). Moderate or severe pain intensity was commonly reported (mean = 5.98, SD = 1.89). Individuals with chronic pain post-stroke reported a range of neuropathic symptoms rather than a common pain experience, with combinations of spontaneous, paroxysmal, and evoked pains in addition to pain associated with paraesthesia/dysaesthesia. Pain involving the upper limb was the most common region (shoulder 39%, hand and forearm 38%), followed by the lower limb (foot 30%, leg 29%). Having multiple strokes was associated with a higher frequency of chronic pain (p = 0.01), as was peripheral vascular disease (p < 0.001) and lipid disorders (p = 0.001). Conclusions: These findings highlight the varied nature of chronic pain experienced by individuals following a stroke, while also detailing stroke and medical history associated with chronic pain. It builds on existing knowledge of chronic pain post-stroke and provides new insight into the neuropathic symptoms experienced. This knowledge has the potential to assist in the development of tailored interventions based on addressing pain symptomatology and health literacy.

Predicting therapy dropout in chronic pain management: a machine learning approach to cannabis treatment

Introduction

Chronic pain affects approximately 30% of the global population, posing a significant public health challenge. Despite their widespread use, traditional pharmacological treatments, such as opioids and NSAIDs, often fail to deliver adequate, long-term relief while exposing patients to risks of addiction and adverse side effects. Given these limitations, medical cannabis has emerged as a promising therapeutic alternative with both analgesic and anti-inflammatory properties. However, its clinical efficacy is hindered by high interindividual variability in treatment response and elevated dropout rates.

Methods

A comprehensive dataset integrating genetic, clinical, and pharmacological information was compiled from 542 Caucasian patients undergoing cannabis-based treatment for chronic pain. A machine learning (ML) model was developed and validated to predict therapy dropout. To identify the most influential factors driving dropout, SHapley Additive exPlanations (SHAP) analysis was performed.

Results

The random forest classifier demonstrated robust performance, achieving a mean accuracy of 80% and a maximum of 86%, with an AUC of 0.86. SHAP analysis revealed that high final VAS scores and elevated THC dosages were the most significant predictors of dropout, both strongly correlated with an increased likelihood of discontinuation. In contrast, baseline therapeutic benefits, CBD dosages, and the CC genotype of the rs1049353 polymorphism in the CNR1 gene were associated with improved adherence.

Discussion

Our findings highlight the potential of ML and pharmacogenetics to personalize cannabis-based therapies, improving adherence and enabling more precise management of chronic pain. This research paves the way for the development of tailored therapeutic strategies that maximize the benefits of medical cannabis while minimizing its side effects.

Chronic orofacial pain and pharmacological management-a clinical guide

Orofacial pain is a widespread health concern that significantly hinders an individual's capacity to engage in daily activities. This type of pain can be classified into three main categories: nociceptive pain, neuropathic pain, and nociplastic pain. Each category involves different mechanisms and requires specific treatment approaches. For optimal treatment of orofacial pain disorders, a multidisciplinary pain management approach is essential. This approach should integrate both nonpharmacological and pharmacological modalities to address the diverse underlying causes and manifestations of pain. In this review, we focus on the current evidence and advancements in the pharmacological management of chronic orofacial pain. We explored the effectiveness of different medications, their mechanisms of action, and their role within a comprehensive pain management plan.

Use of C-Reactive Protein in Global Leadership Initiative on Malnutrition (GLIM) Etiologic Criteria for Critically Ill Patients: A Retrospective Claims Database Study

Background/Objectives: The Global Leadership Initiative on Malnutrition (GLIM) is suggested by major societies. The etiologic criteria for inflammation in critically ill patients remain unclear. Because an initial nutritional assessment is recommended within 48 h, it is also possible to use C-reactive protein (CRP) up to 3 days after admission. The purpose of the present study is to explore the utility of CRP in identifying malnutrition and to determine whether a nutritional assessment incorporating CRP criteria can effectively identify malnourished patients in the intensive care unit (ICU). Methods: This was a retrospective cohort study of ICU patients. The primary outcome was a composite of in-hospital mortality, Barthel index < 60 at discharge, and length of hospital stay of 14 days or more. The area under the curve (AUC) for the primary outcome was calculated using CRP between days 0 and 2. We divided the patients into four groups using inflammation criteria with the optimal cut-off and low body mass index (BMI) criteria of the GLIM: CRP+/-, and BMI+/-. Results: A total of 38,981 patients were included. The AUC of the highest CRP between days 0 and 2 was 0.65, which was higher than the CRP on day 0 and the highest CRP between days 0 and 1 (0.59 and 0.63). The AUC and optimal cut-offs varied depending on diagnoses, with a maximum of 0.75 in neurology. The optimal cut-off for the maximum CRP was 3.82 mg/dL. In the four groups of CRP+BMI+, CRP+BMI-, CRP-BMI+, and CRP-BMI-, the in-hospital mortality values were 22.7, 14.4, 10.8, and 4.8% (p < 0.001 between all the groups). Conclusions: In an initial nutritional assessment of critically ill patients, it would be appropriate to use the maximum CRP over 3 days from ICU admission.

Mitochondria and astrocyte reactivity: Key mechanism behind neuronal injury

In this special issue to celebrate the 30th anniversary of the Uruguayan Society for Neuroscience (SNU), we find it pertinent to highlight that research on glial cells in Uruguay began almost alongside the history of SNU and contributed to the understanding of neuron-glia interactions within the international scientific community. Glial cells, particularly astrocytes, traditionally regarded as supportive components in the central nervous system (CNS), undergo notable morphological and functional alterations in response to neuronal damage, a phenomenon referred to as glial reactivity. Among the myriad functions of astrocytes, metabolic support holds significant relevance for neuronal function, given the high energy demand of the nervous system. Although astrocytes are typically considered to exhibit low mitochondrial respiratory chain activity, they possess a noteworthy mitochondrial network. Interestingly, both the morphology and activity of these organelles change following glial reactivity. Despite receiving less attention compared to studies on neuronal mitochondria, recent studies indicate that mitochondria play a crucial role in driving the transition of astrocytes from a quiescent to a reactive state in various neurological disorders. Notably, stimulating mitochondria in astrocytes has been shown to reduce damage associated with the neurodegenerative disease amyotrophic lateral sclerosis. Here, we focus on studies supporting the emerging paradigm that metabolic reprogramming occurs in astrocytes following damage, which is associated with their phenotypic shift to a new functional state that significantly influences the progression of pathology. Thus, exploring mitochondrial activity and metabolic reprogramming within glial cells may provide valuable insights for developing innovative therapeutic approaches to mitigate neuronal damage. In this review, we focus on studies supporting the emerging paradigm that metabolic reprogramming occurs in astrocytes following damage, which is associated with their phenotypic shift to a new functional state that significantly influences the progression of pathology. Thus, exploring mitochondrial activity and metabolic reprogramming within glial cells may provide valuable insights for developing innovative therapeutic approaches to mitigate neuronal damage.

Can physical and psychological factors predict pain recurrence or an exacerbation of persistent non-specific low back pain? A protocol for a systematic review and meta-analysis

INTRODUCTION

Low back pain (LBP) is a global health concern. Approximately two-thirds of those who recover from LBP experience a relapse within a year, with many chronic cases encountering acute flare-ups (exacerbation). This systematic review will synthesise and analyse whether physical and/or psychological features can predict recurrent episodes of LBP or exacerbation of pain.

METHODS AND ANALYSIS

This systematic review protocol follows the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines. Comprehensive literature searches will be conducted in MEDLINE, EMBASE, APA PsycInfo, PubMed, CINAHL Plus, Web of Science, Scopus and ZETOC, spanning from each database's inception through to January 2025. Google Scholar and grey literature sources, including OpenGrey, will also be searched to ensure comprehensive coverage. Two independent reviewers will screen titles, abstracts and full texts, assessing the risk of bias with a modified Quality in Prognosis Studies tool. The overall certainty of evidence will be evaluated using an adapted Grading of Recommendations Assessment, Development and Evaluation approach. If sufficient data homogeneity is present, a meta-analysis will be performed; otherwise, findings will be synthesised narratively. The results will identify the ability of physical and/or psychological factors to predict pain recurrence or acute exacerbation in case of persistent non-specific LBP.

ETHICS AND DISSEMINATION

This study protocol does not present any ethical concerns. The findings from the systematic review will be submitted for publication in a peer-reviewed journal and will also be presented at relevant conferences.

PROSPERO REGISTRATION NUMBER

CRD42024599514.

The Impact of Standard Care Versus Intrinsic Relaxation at Home on Physiological Parameters in Patients with Fibromyalgia: A Comparative Cohort Study from Romania

Background and Objectives: Fibromyalgia (FM), through the presence of widespread chronic pain, stiffens the musculoskeletal system and causes sleep disturbances and fatigue. Through this study, we aimed to compare the effectiveness of two different recovery interventions for improving sleep quality: a standard, multidisciplinary intervention in a recovery hospital versus a therapy focused on intrinsic relaxation at home. Materials and Methods: This study included 60 adult patients who participated voluntarily and were diagnosed with FM by a rheumatologist, randomly divided into two groups. During this study, 30 patients out of the 60 were randomly assigned to experimental group 1 and underwent treatment at the Recovery Clinical Hospital in Băile Felix. The other 30 patients were assigned to experimental group 2 and underwent treatment at home. They were assessed on the first and last day of the recovery program using the Fatigue Severity Scale (FSS) and the Pittsburgh Sleep Quality Index (PSQI). Results: In experimental group 1, where by patients underwent hospital recovery (EG1), the results show that the severity of fatigue (FSS) was significantly reduced, with p = 0.00 and an effect size of 0.77, which suggests a general improvement in the state of fatigue, as well as in the quality of sleep evaluated with the PSQI (p = 0.00, effect size = 0.55). In experimental group 2 (EG2), no change was observed between assessments in terms of the FSS, but in terms of the quality of sleep, there was a small decrease in the PSQI score (p = 0.083), with a small effect size of 0.09. Conclusions: The results show that, from a clinical point of view, a complex treatment carried out daily improves sleep quality and reduces fatigue.

Association between C-reactive protein and chronic pain in US adults: A nationwide cross-sectional study

BACKGROUND

Chronic pain has emerged as a significant global public health concern. Hence, it is imperative to acquire a more comprehensive comprehension of these characteristics in the adult population of the United States in order to facilitate the development of effective interventions. The objective of this study is to ascertain the prevalence of chronic pain among people in the United States and investigate its association with C-reactive protein (CRP) levels.

METHODS

The present study employed a cross-sectional design and utilized data from three cycles of the National Health and Nutrition Examination Survey (NHANES). The study aimed to investigate the relationship between chronic pain status, CRP levels, and potential confounding factors. The study incorporated individuals who successfully fulfilled chronic questionnaires and had CRP assays. Weighted univariate and multivariate logistic regression analyses were performed to examine the correlation between chronic pain and CRP levels. To explore the non-linear relationship, weighted restricted cubic spline (RCS) with three knots coupled with a weighted logistic regression model to assess the dose-response relationship between CRP (continuous variables) and chronic pain.

RESULTS

A total of 10,680 (Weighted 250,814,660.8) adult participants with complete information were included in the analysis and 2612 (Weighted 67978784.88, 27.1%) subjects met the definition of chronic pain. Compared with participants without chronic pain, those with chronic pain had a higher CRP level (P < 0.001). The results of the multivariable adjusted logistic regression model suggested that the highest CRP quartile (CRP >  0.52 mg/dL) was associated with a 32% increase in the risk of chronic pain compared with the lowest CRP quartile (CRP ≤  0.09 mg/dL). The RCS result showed that the OR of chronic pain and CRP displayed a linear relationship (P = 0.027, Non-linear P = 0.541).

CONCLUSIONS

The study found a significant correlation between CRP levels and the presence of chronic pain among people in the United States. Individuals exhibiting elevated levels of CRP demonstrated a heightened propensity for experiencing chronic pain in comparison to individuals with lower CRP levels. Additional investigation is necessary to explore the presence of a causal association between the two variables, as well as the potential underlying mechanisms.

Piano level laser therapy versus epidermal growth factor injection for painful myogenic temporomandibular disorder (a randomized clinical trial)

OBJECTIVE

The aim of this clinical trial was to evaluate the effectiveness of Piano level laser therapy using Nd-YAG laser and intramuscular EGF injection in pain alleviation, function, and quality of life improvement in patients suffering from myogenic TMD.

MATERIALS AND METHODS

A randomized clinical trial was performed on 29 patients suffering from chronic painful myogenic TMD based on diagnostic criteria for temporomandibular disorders. Group I (n = 13patients) was treated using 1064 nm Nd-YAG Laser (4 sessions once/week). Group II (n = 14 patients) was treated by intramuscular injection of EGF. Pain using numerical rating score, pain free opening and unassisted maximum opening were measured at baseline, 7,14,21 days, 1 and 3 months. Quality of life using OHIP-14 was assessed at baseline, 1 and 3 months.

RESULTS

Results showed that there was a significant pain reduction (P < 0.000) and increase in pain free opening (P < 0.0001) in both test groups. However, only group I showed a significant increase in maximum opening (P = 0.007). Quality of life significantly improved in both groups (P = 0.0001). There was no significant difference between the two treatments in pain scores, pain free opening, maximum opening nor quality of life.

CONCLUSION

Both treatment modalities offered effective and cost-effective non- to minimally invasive treatment options for myogenic TMD with no side effects.

CLINICAL RELEVANCE

Myogenic TMD forms a public health issue and is a common musculoskeletal problem causing pain and disability. The proposal of effective, non-invasive, and affordable treatment options can help solve this issue.

Integrated bioinformatics analysis of the effects of chronic pain on patients with spinal cord injury

Background

Spinal cord injury (SCI) poses a substantial challenge in contemporary medicine, significantly impacting patients and society. Emerging research highlights a strong association between SCI and chronic pain, yet the molecular mechanisms remain poorly understood. To address this, we conducted bioinformatics and systems biology analyses to identify molecular biomarkers and pathways that link SCI to chronic pain. This study aims to elucidate these mechanisms and identify potential therapeutic targets.

Methods

Through analysis of the GSE151371 and GSE177034 databases, we identified differentially expressed genes (DEGs) linked to SCI and chronic pain. This analysis uncovered shared pathways, proteins, transcription factor networks, hub genes, and potential therapeutic drugs. Regression analysis on the hub genes facilitated the development of a prognostic risk model. Additionally, we conducted an in-depth examination of immune infiltration in SCI to elucidate its correlation with chronic pain.

Results

Analyzing 101 DEGs associated with SCI and chronic pain, we constructed a protein interaction network and identified 15 hub genes. Using bioinformatics tools, we further identified 4 potential candidate genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed a strong correlation between SCI and chronic pain, particularly related to inflammation. Additionally, we examined the relationship between SCI and immune cell infiltration, discovering a significant link between SCI and T cell activation. This is notable as activated T cells can cause persistent inflammation and chronic pain. Lastly, we analyzed the hub genes to explore the transcription factor network, potential therapeutic drugs, and ceRNA networks.

Conclusion

The analysis of 15 hub genes as significant biological markers for SCI and chronic pain has led to the identification of several potential drugs for treatment.

Orofacial pain models induce impairment in spatial learning and working memory in rodents: A systematic review and meta-analysis

Orofacial pain is one of the most common causes of chronic pain leading to physical and cognitive disability. Several clinical and pre-clinical studies suggest that chronic pain results in cognitive impairment. However, there is a lack of meta-analyses examining the effects of orofacial pain models on behavioral learning and memory in rodents. Thus, this study aimed to evaluate whether orofacial pain models can impair learning and memory in rodents. The protocol was registered in PROSPERO (CRD42023355502). We used CAMARADES and SYRCLE to estimate the quality and the publication bias by using Egger's and Begg's test. Here, 21 studies were included in this systematic review and meta-analysis. We included 12 studies with trigeminal neuralgia models, 4 with migraine-like pain models, 4 with tooth nociception, and 1 with acute orofacial pain model. Spontaneous nociception and facial mechanical allodynia were observed in orofacial pain models. Regarding spatial learning we detected that latency to find the platform in the Morris water maze (MWM) was increased in orofacial pain models (related to facial mechanical allodynia or spontaneous nociception). Although the mean quality of the articles was high, we identify publication bias in the Begg's test for the time in the quadrant in the MWM. Our findings revealed that spontaneous nociception and facial mechanical allodynia in orofacial pain models contribute to the working memory and spatial learning dysfunction. Therefore, further studies are still needed to evaluate the influence of sex, age, social isolation, and environmental enrichment in orofacial pain-related learning and memory.

Chronic postsurgical inguinal pain: incidence and diagnostic biomarkers from a large German national claims database

BACKGROUND

Chronic postsurgical inguinal pain (CPIP) is the most common complication of groin hernia surgery. The characteristics of patients, their medical care, and choice of diagnostic tools remain to be defined to optimise preventive and therapeutic interventions.

METHODS

Claims data from 2018 and a 1-yr follow-up were analysed for incidence and medical care. A separate cohort (141 healthy controls and 17 CPIP patients) was examined by deep phenotyping. This included sensory testing, blood and skin biopsies, MRI of the dorsal root ganglion (DRG), and patient-reported outcomes.

RESULTS

Of 11,221 patients with hernia surgery in 2018 identified, 8.5% had pain before that was relieved by surgery, but a similar percentage had novel pain in this region. Deep phenotyping of 141 healthy controls provided a map of the inguinal sensory system. The following analysis of patients with CPIP revealed that they suffered from moderate pain with neuropathic features, individual sensory abnormalities, and unilateral L1 DRG atrophy. In the blood, levels of C-C-motif chemokine ligand (CCL2) and brain-derived neurotrophic factor (BDNF) were upregulated, whereas apolipoprotein A1 (ApoA1) concentration was reduced. A cluster of DRG atrophy, BDNF, ApoA1, and anxiety correlated best with the diagnosis. CPIP patients with novel pain had significantly more DRG atrophy (-24% ipsilateral vs contralateral volume).

CONCLUSIONS

CPIP is often newly acquired after surgery. A combination of DRG imaging, serum markers, and anxiety screening can support the diagnosis. In the future, this could guide clinicians towards more personalised therapies (e.g. targeting anxiety or lipid profiles) and possible altered surgical techniques.

CLINICAL TRIAL REGISTRATION

German Trial Registry DRKS00024588 and DRKS00016790.

From: "It's just how she walks …" to "… any lameness is a welfare issue" - UK stakeholders' perspectives on chronic lameness in dairy cows

Lameness in dairy cows is a prevalent welfare problem and imposes direct and indirect economic costs on producers. Lameness can be acute or chronic, however, a shared definition of what constitutes chronic lameness is currently lacking amongst stakeholders. Our study used structured interviews to address this gap. We interviewed 22 UK-based participants (eight veterinarians, eight dairy farmers, three foot-trimmers; two were veterinarians and dairy farmers; another was a farmer and foot trimmer). Stakeholder responses found good agreement with work done by previous authors, e.g., on behavioral and production-related lameness indicators; and that lame cows experience pain because of their lameness and, thus, suffer compromised welfare. Participants used descriptive terms (e.g., "recurrent") and suggested measurable characteristics (e.g., bout duration) to define chronic lameness. Stakeholders reported that chronic lameness not only affects cow welfare but also reduces the wellbeing of people working with them; and also raised concerns over the environmental costs of chronic lameness, such as increased culling and reduced sustainability. Developing some of our findings into a future definition of chronic lameness would be the first step in understanding and quantifying the extent of this problem.

Similarities and differences between chronic primary pain and depression in brain activities: Evidence from resting-state microstates and auditory Oddball task

BACKGROUND

In 2019, the International Association for the Study of Pain introduced the concept of 'chronic primary pain (CPP)', characterized by persistent non-organic pain with emotional and functional abnormalities. Underdiagnosed and linked to depression, CPP has poorly understood neural characteristics. Electroencephalogram (EEG) microstates enable detailed examination of brain network dynamics at the millisecond level. Incorporating task-related EEG features offers a comprehensive neurophysiological signature of brain dysfunction, facilitating exploration of potential neural mechanisms.

METHODS

This study employed resting-state and task-related auditory Oddball EEG paradigm to evaluate 20 healthy controls, 20 patients with depression, and 20 patients with CPP. An 8-minute recording of resting-state EEG was conducted to identify four typical microstates (A-D). Additionally, power spectral density (PSD) features were examined during an auditory Oddball paradigm.

RESULTS

Both CPP and Major Depressive Disorder (MDD) patients exhibited reduced occurrence rate and transition probabilities of other microstates to microstate C during resting-state EEG. Furthermore, more pronounced increase in Gamma PSD was observed in the occipital region of CPP during the Oddball task. In CPP, both resting-state microstate C and task-related Gamma PSD correlated with pain and emotional indicators. Notably, microstate C occurrence positively correlated with occipital Gamma PSD in MDD.

CONCLUSION

Conclusively, both CPP and MDD display dynamic abnormalities within the salient network, closely associated with pain and depressive symptoms in CPP. Unlike MDD, CPPs' dynamic network changes appear unrelated to perceptual integration function, indicating differing microstate functional impacts. Combining resting-state microstates and Oddball tasks may offer a promising avenue for identifying potential biomarkers in objectively assessing chronic primary pain.

Fibromyalgia: Understanding, Diagnosis and Modern Approaches to Treatment

Fibromyalgia (FM) is a chronic condition characterized by generalized musculoskeletal pain associated with other symptoms, especially sleep and mood disorders, fatigue, and cognitive dysfunctions. The etiopathogenesis of FM is not sufficiently known, and regardless of numerous research, the clinical presentation is nonspecific, which makes it difficult to approve a timely diagnosis and, subsequently, an adequate therapeutic approach. Genetic, hormonal, immunological, and environmental factors are cited as potential factors in the development of this condition. Diagnosis is based on a clinical approach and known diagnostic criteria, while additional methods, such as radiographic, magnetic resonance, or laboratory analyses, can be useful to exclude other conditions. The heterogeneity of FM significantly impacts both diagnosis and treatment, as it presents a wide spectrum of symptoms that vary in severity, combinations, and underlying contributing factors. This variability is a challenge for clinicians and requires a holistic, comprehensive, multidisciplinary, patient-centered approach. According to The European League Against Rheumatism (EULAR) from 2016, treatment begins with patient education and involves the simultaneous application of pharmacological and nonpharmacological treatments. The application of only pharmacological or nonpharmacological treatment is most often not successful. Due to differences in pain threshold, psychological factors, and comorbidities, patients may respond differently to the same interventions. Although there is no universal treatment, this review brings up the fact that the timely recognition of symptoms and a tailored treatment with a patient-centered plan can significantly improve the quality of life of patients.

Aerobic Exercise Prescription for Pain Reduction in Fibromyalgia: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVE

Fibromyalgia is a condition characterised by disabling levels of pain of varying intensity. Aerobic exercise may play a role in reducing pain in these patients. The aim of this review is to assess the dose of aerobic exercise needed, based on the frequency, intensity, type, time, volume and progression (FITT-VP) model, to obtain clinically relevant reductions in pain.

DATABASES AND DATA TREATMENT

A systematic review and meta-analysis of randomised clinical trials was conducted in the Web of Science (WoS), PEDro, PubMed and Scopus databases, the search having been conducted between July and October of 2023. Risk of bias was assessed with the Cochrane Risk of Bias assessment tool 2.

RESULTS

Seventeen studies were included. The risk of bias varied, with six studies showing low risk; five, some concerns; and six, high risk. Aerobic exercise interventions were analysed using the FITT-VP model. Frequency ranged from 1 to 10 times per week, intensity varied from light to vigorous, and the types of exercise included music-based exercise, interval training, pool-based exercise, stationary cycling, swimming and walking. The intervention durations ranged from 3 to 24 weeks, with session lengths ranging from 10 to 45 min. Most of the studies presented significant differences, favouring aerobic exercise (MD -0.49; CI [-0.90, -0.08; p = 0.02]), with moderate to low heterogeneity in subgroup analyses.

CONCLUSIONS

The study findings underscore the efficacy of aerobic exercise in alleviating pain among fibromyalgia patients, advocating for tailored exercise dosing to optimise adherence and outcomes.

SIGNIFICANCE STATEMENT

Individuals with fibromyalgia should engage in aerobic exercises two to three times weekly, for twenty-five to forty minutes in each session, aiming for more than a hundred minutes per week. They should start at low intensity, gradually increasing to higher intensities over six to twelve weeks, for optimal pain management. Exercise types should be selected in collaboration with the patient and based on personal preferences and accessibility, such as walking, and swimming, to ensure long-term adherence to the regimen.

Mechanisms and Therapeutic Potential of GPX4 in Pain Modulation

Pain, a complex symptom encompassing both sensory and emotional dimensions, constitutes a significant global public health issue. Oxidative stress is a pivotal factor in the complex pathophysiology of pain, with glutathione peroxidase 4 (GPX4) recognized as a crucial antioxidant enzyme involved in both antioxidant defense mechanisms and ferroptosis pathways. This review systematically explores GPX4's functions across various pain models, including neuropathic, inflammatory, low back, and cancer-related pain. Specifically, the focus includes GPX4's physiological roles, antioxidant defense mechanisms, regulation of ferroptosis, involvement in signal transduction pathways, and metabolic regulation. By summarizing current research, we highlight the potential of GPX4-targeted therapies in pain management.

Causes and management of acute oncological pain: a narrative review

INTRODUCTION

Acute pain in cancer is an important but often overlooked feature of many patients' oncological journey. Cancer-related pain is associated commonly with more persistent pain states caused by both the disease and its treatment, but there are numerous causes of acute pain which can develop in patients with cancer. This pain is frequently severe, can be challenging to manage and its suboptimal control can directly impact on oncological outcomes. This narrative review provides an overview of several causes of acute pain in patients with cancer and management approaches.

METHODS

A focused literature review was conducted to encompass the search terms 'acute pain', 'oncology' and 'cancer' in adult and paediatric populations.

RESULTS

Acute pain is common in patients with cancer with a number of pain generators identified. Broadly, these are disease- and treatment-related but commonality in pain mechanisms and features are present. Importantly, these pain states do not occur in isolation; a patient may experience multiple acute pain episodes during their oncology journey.

DISCUSSION

As the oncological treatment landscape shifts and increasing numbers of novel treatments are employed, the number of causes of acute pain in patients with cancer rises. This pain is often managed by non-pain specialists and suboptimal control has a variety of deleterious effects. It is important that awareness of acute pain in the oncological population is increased and treatment approaches, which adopt a biopsychosocial structure, are optimised.

Problems accessing pain care, and the adverse outcomes among adults with chronic pain: a cross-sectional survey study

AIMS

Prescribing restrictions have significantly impacted patients with chronic pain, leading to opioid medication tapering and reduced access. This study examines the consequences of these restrictions and their impact on patient health and pain management strategies.

PATIENTS & METHODS/MATERIALS & METHODS

This research explores barriers to pain care, especially opioid therapy, adverse health outcomes resulting from reduced access to pain medications, and alternative pain management strategies. The study analyzes data from a cross-sectional survey conducted by the American Chronic Pain Association (ACPA) between November 2014 and January 2015. The survey gathered quantitative data on demographics, healthcare access, pain management strategies, and challenges in obtaining prescribed medications, alongside qualitative responses. Descriptive statistics summarized quantitative findings; chi-square and t-tests compared those with and without medication access difficulties. Thematic analysis revealed recurring themes in qualitative responses.

RESULTS

The study reveals that over half of the respondents faced difficulties obtaining prescribed pain medications, leading to significant adverse health consequences, including unmanaged pain, psychological distress, and suicidal ideation.

CONCLUSION

These findings highlight the urgent need to address systemic and personal barriers to pain medication access, and the need for patient-centered care that incorporates evidence-based, holistic pain management strategies and shared decision-making between clinicians and patients.

Monitoring Chronic Non-Cancer Pain in Denmark Over Two Decades: Prevalence, Mental Health and Loneliness

BACKGROUND

Epidemiological surveys have monitored chronic non-cancer pain (CNCP) and investigated associated factors in Denmark for more than 20 years. This study aimed to analyse CNCP prevalence in the Danish population from 2000 to 2023 and its associations with mental health status and loneliness.

METHODS

Population-based surveys were conducted between 2000 and 2023. In all waves, residents aged ≥ 16 years were randomly selected to complete a self-administered questionnaire. Samples included 10,089 respondents in 2000, 5292 in 2005, 14,330 in 2010, 13,429 in 2013, 13,050 in 2017, 10,384 in 2021 and 9303 in 2023. CNCP was defined as pain lasting ≥ 6 months. Mental status was assessed by Mental Component Summary score of Short Form-12 and severe loneliness by the Three-Item Loneliness Scale. Calibration weighting was applied to reduce potential non-response bias.

RESULTS

The prevalence of CNCP increased steadily by 9.4 percentage points from 2000 (19.5%) to 2023 (28.9%), but with a downward tick during the COVID-19 pandemic in 2021 (25.3%). Women aged 45 years or older had the highest prevalence in all waves. Results showed a worsening of mental health over time in both individuals with and without CNCP; however, the lowest scores were reported by individuals with CNCP. Severe loneliness seemed to be a substantial problem in individuals with CNCP (17.3% in 2021).

CONCLUSIONS

In summary, CNCP was highly prevalent over the given period and associated with mental health status and severe loneliness in recent years.

SIGNIFICANCE

This study demonstrated alarming trend on chronic non-cancer pain prevalence over time in Denmark. The high estimates of prevalence and related issues, such as mental health and severe loneliness deserve further investigation and prioritisation in the public health agenda.

What has brain diffusion magnetic resonance imaging taught us about chronic primary pain: a narrative review

ABSTRACT

Chronic pain is a pervasive and debilitating condition with increasing implications for public health, affecting millions of individuals worldwide. Despite its high prevalence, the underlying neural mechanisms and pathophysiology remain only partly understood. Since its introduction 35 years ago, brain diffusion magnetic resonance imaging (MRI) has emerged as a powerful tool to investigate changes in white matter microstructure and connectivity associated with chronic pain. This review synthesizes findings from 58 articles that constitute the current research landscape, covering methods and key discoveries. We discuss the evidence supporting the role of altered white matter microstructure and connectivity in chronic primary pain conditions, highlighting the importance of studying multiple chronic pain syndromes to identify common neurobiological pathways. We also explore the prospective clinical utility of diffusion MRI, such as its role in identifying diagnostic, prognostic, and therapeutic biomarkers. Furthermore, we address shortcomings and challenges associated with brain diffusion MRI in chronic primary pain studies, emphasizing the need for the harmonization of data acquisition and analysis methods. We conclude by highlighting emerging approaches and prospective avenues in the field that may provide new insights into the pathophysiology of chronic pain and potential new therapeutic targets. Because of the limited current body of research and unidentified targeted therapeutic strategies, we are forced to conclude that further research is required. However, we believe that brain diffusion MRI presents a promising opportunity for enhancing our understanding of chronic pain and improving clinical outcomes.

Correlates of chronic pain onset and recovery in the CoLaus cohort

BACKGROUND

Only few previous cohort studies examined simultaneously predictors of chronic pain (CP) onset and recovery. Furthermore, these studies used various sociodemographic and pain-related characteristics, without standardized measures of sleep and depression. The present study aimed at expanding and strengthening these findings in a large Swiss population.

METHODS

We analysed data from a longitudinal cohort (n = 4602) collected at two time points separated by 5 years in Lausanne, Switzerland. We studied through two independent multivariable logistic regression models, the predictors of CP onset and recovery, including socio-demographic data as well as standardized measures of sleep and mood.

RESULTS

Chronic pain was reported by 43.1% and 44.4% of participants, with 11.6% at the second follow-up reporting moderate or intense pain. Neuropathic pain, regardless of intensity, had a more negative impact on quality of life. An inferential model (n = 1331) identified the male sex as predictive for recovering from CP. Older age, being overweight or obese (compared to normal weight), higher depression scores and pain medication intake were predictive for sustained pain at the second follow-up. A second model (n = 1886) identified being overweight or obese (compared to normal weight), low quality of sleep and being a former smoker (compared to a non-smoker) as predictive for developing CP, while the male sex was lowering the risk.

CONCLUSIONS

While sex and weight are associated with both recovery and new CP onset, separate variables also need to be considered in these processes, underlining specific factors to be addressed, depending on the context, whether preventive or therapeutic.

SIGNIFICANCE STATEMENT

Multivariable models in a Swiss cohort (N = 4602) associate male sex, not taking pain medication, normal weight, lower depression scores and younger age with recovery from chronic pain, while females, obese or overweight, having worse sleep and former smokers are associated with onset of new chronic pain. These common and separate factors need to be considered in treatment and prevention efforts.

Pharmacological interventions for patients with chronic primary musculoskeletal pain: disparity between synthesized evidence and real-world clinical practice

Introduction

Chronic primary musculoskeletal pain (CPMP) poses a major problem of public health, with high prevalence rates and economic burden. There is a wealth of clinical trials examining pharmacological interventions for patients with CPMP. Nevertheless, evidence from such trials does not necessarily mirror clinical realities.

Objectives

We aimed to compare data sets from a clinical sample with an randomized controlled trial (RCT)-based sample.

Methods

Both data sets included participants living with CPMP who received pharmacological interventions. The clinical sample was retrieved from electronic health records. The RCT-based sample stemmed from a network meta-analysis project. The following outcomes were used: demographic information, diagnosis-specific data, and pharmacological interventions (categorized according to the World Health Organization [WHO] analgesic ladder).

Results

The clinical sample consisted of 103 patients (mean age: 50.25 years; SD: 14.0) and the RCT-based samples contributed 8665 participants (mean age: 51.97 years; SD: 6.74). In both samples, the proportion of women was higher than that of men (ie, 74.8% vs 58.9%). Psychiatric disorders were the most common comorbidities in the clinic sample but also the most frequent reason for patient exclusion in RCTs. The 2 samples differed significantly in medication classified as WHO III (clinical sample: 12.9%; RCT sample: 23.5%; P = 0.023) and WHO IV (clinical sample: 23.4%; RCT sample: 8.6%; P < 0.001), yet not WHO I and II.

Conclusion

Our findings suggest a disparity between research-based study populations and clinical populations with CPMP. We advocate for future investigations on how to implement robust scientific evidence into real-world clinical practice, with a particular focus on addressing psychiatric comorbidities.

Co-occurrence of mental distress and insomnia associates with more severe musculoskeletal pain - Northern Finland Birth Cohort 1966 study

OBJECTIVE

This cross-sectional study demonstrates the differences in the dimensions of musculoskeletal (MSK) pain between participants with mental distress and/or insomnia among general population with MSK pain within the past 12 months.

METHODS

Participants of Northern Finland Birth Cohort 1966 (NFBC1966) were studied (n = 4316). They were divided into groups based on their mental distress and insomnia status (co-occurring mental distress and insomnia [CMI], isolated mental distress [M] and insomnia [I], and absence of both [AMI]). The AMI group was used as a reference for the main analyses. The dimensions of MSK pain included frequency, bothersomeness (Numerical Rating Scale [NRS] 0-10), intensity of pain (NRS), and number of pain sites (1-8). Multinomial and general linear regression analyses were used to study the associations, and adjustments were made for sex, education, number of somatic diseases, and physical activity.

RESULTS

The CMI group was associated with more severe pain in every dimension when contrasted to all other groups (daily pain adjusted OR 5.08, 95 % CI 3.43-7.51; bothersomeness adjusted β 1.7, 95 % CI 1.5-2.0; intensity adjusted β 1.4, 95 % CI 1.2-1.7; number of pain sites adjusted β 1.2, 95 % CI 1.0-1.4). Compared to AMI, I and M groups also had relationships with all pain dimensions, but with lower magnitude compared to the CMI group.

CONCLUSIONS

The results suggest that insomnia and mental distress co-exist with more severe MSK pain, and when co-occurring, MSK pain severity tends to increase. Therefore, contemplating insomnia and mental distress are important to consider when comprehensively evaluating MSK pain symptoms.

11th revision of the International Classification of Diseases chronic primary pain diagnoses in children and adolescents: representation of pediatric patients in the new classification system

ABSTRACT

Chronic pain is common among children and adolescents; however, the diagnoses in the newly developed 11th revision of the International Classification of Diseases (ICD-11) chronic pain chapter are based on adult criteria, overlooking pediatric neurodevelopmental differences. The chronic pain diagnoses have demonstrated good clinical applicability in adults, but to date, no field study has examined these diagnoses to the most specific diagnostic level in a pediatric sample. The current study aimed to explore pediatric representation within the ICD-11, with focus on chronic primary pain. Healthcare professionals (HCPs) at a specialized pediatric pain center documented the symptoms of and assigned both ICD-10 and ICD-11 diagnoses to N = 402 patients. Using criteria-based computer algorithms, specific ICD-11 pain diagnoses were allocated for each documented pain location, with residual diagnoses (ie, "unspecified") assigned if criteria were not (fully) met. Within the ICD-11, the algorithms assigned specific pain diagnoses to most patients (73.6%). In ICD-10, HCPs could not specify a diagnosis for 5.2% of patients; the ICD-11 algorithm allocated a residual chronic primary pain diagnosis in 51.2%. Residual categories were especially prevalent among younger children, boys, patients with headaches, and those with lower pain severity. Overall, clinical utility of the ICD-11 was high, although less effective for chronic back pain and headache diagnoses. The latter also exhibited the lowest agreement between HCPs and algorithm. The current study underscores the need for evidence-based improvements to the ICD-11 diagnostic criteria in pediatrics. Developing pediatric coding notes could improve the visibility of patients internationally and improve the likelihood of receiving reimbursement for necessary treatments through accurate coding.

Pain in Tourette Syndrome: A Comprehensive Review

Objectives: Recent survey data suggest that a high proportion of patients with Tourette syndrome (TS) experience pain, yet pain features in TS have not been previously investigated in a systematic manner. This article reviews the current understanding and impact of pain in TS as well as identifies possible areas for emphasis for future research on pain in TS. Methods: Using a comprehensive search strategy in two relevant research databases (PubMed and Scopus), we searched for relevant peer-reviewed, primary research articles, and review articles. Search terms used were Tourette syndrome, tic disorder, pain, pain management, sensory, and sensory gating. Results: A total of 116 pertinent articles were identified. Pain is reported by 47%-60% of individuals with TS and may relate to different aspects of tic phenomenology or other causes. Pain is more prevalent among TS patients than in the general population and negatively impacts quality of life. To standardize future research efforts, we propose the following classification: tic-related immediate pain, tic-related delayed injury/pain, suppression-related pain, premonitory urge-related pain, and associated primary pain syndromes. Altered sensory gating and interoceptive processing abnormalities are possible mechanisms contributing to pain in TS but warrant further study. Despite pain prevalence, most TS clinical rating scales and outcome measures used in therapeutic studies do not incorporate sufficient information regarding pain. Therapies known to improve pain in non-TS conditions that are also reported to improve tics have not been investigated for their effects on pain among TS patients. Conclusion: TS can be associated with a chronic pain syndrome that negatively affects quality of life. Future research using a systematic framework is needed to better understand pain cause(s) and prevalence, develop appropriate assessment methods, establish outcome measures, and understand mechanisms of pain in TS. Such investigations are likely to lead to therapeutic options for this troublesome symptom.

Do cytokines play a role in the transition from acute to chronic musculoskeletal pain?

Musculoskeletal pain has a high prevalence of transition to chronic pain and/or persistence as chronic pain for years or even a lifetime. Possible mechanisms for the development of such pain states are often reflected in inflammatory or neuropathic processes involving, among others, cytokines and other molecules. Since biologics such as blockers of TNF or IL-6 can attenuate inflammation and pain in a subset of patients with rheumatoid arthritis, the question arises to what extent cytokines are involved in the generation of pain in human musculoskeletal diseases. In numerous experimental non-human studies, cytokines have been shown to alter neuronal sensitivity in the peripheral and central nociceptive systems. In this review, we addressed the involvement of cytokines in postoperative pain, complex regional pain syndrome, rheumatoid arthritis, osteoarthritis, temporomandibular joint disease, low back pain and fibromyalgia using PubMed searches including meta-analyses of data. There is evidence that certain pro- and anti-inflammatory cytokines are regulated in all of these diseases, often in both acute and chronic disease states. However, within these data, we found a great deal of heterogeneity in the association between cytokine levels and pain. Neutralization of cytokines showed antinociceptive effects in subgroups of patients with chronic pain (e.g., in a proportion of patients with rheumatoid arthritis), but failed to reduce chronic pain in other diseases (e.g., osteoarthritis). More systematic studies are needed to unravel the pathogenic role of cytokines in human musculoskeletal pain, taking into account the disease process and the mechanisms of pain initiation and maintenance.

The burden of chronic pain in transgender and gender diverse populations: Evidence from a large US clinical database

BACKGROUND

Chronic pain, affecting approximately 20% of the global population, is the leading cause of disability worldwide. Transgender individuals are disproportionately exposed to chronic pain risk factors compared with the cisgender population. This study compares the incidence of chronic pain between transgender and cisgender individuals and examines the impact of gender affirming hormone therapy, anxiety, and depression on chronic pain.

METHODS

The study analysed medical records data of 56,470 transgender men and 41,882 transgender women in the TrinetX database. Six cohorts were created: transgender women either receiving oestrogen or no intervention, transgender men receiving testosterone or no intervention and cohorts of cisgender males and females. Unmatched age-adjusted incidence rates were calculated. Then cohorts were matched on 22 chronic pain-associated covariates and the rate of new chronic pain diagnoses was compared between those receiving hormone therapy and those without.

RESULTS

We observed significantly higher rates of chronic pain among transgender individuals compared with cisgender counterparts. Transgender men on testosterone therapy and transgender women on oestrogen therapy exhibited an increased likelihood of chronic pain diagnoses compared with those not receiving hormone therapy. Individuals with anxiety and depression were more likely to be diagnosed with chronic pain.

CONCLUSION

This study demonstrates a significant burden of chronic pain in transgender individuals, with an increased risk among those receiving hormone therapy. Our study, the first to assess chronic pain in a large cohort of transgender patients, provides support for a potential association between hormone therapy and risk of chronic pain diagnosis. Further research is required to understand causal mechanisms and to develop improved screening and management of chronic pain in transgender populations.

SIGNIFICANCE STATEMENT

Our study, featuring the largest cohort of Transgender and Gender Diverse (TGD) individuals assembled to date, reveals critical disparities in chronic pain among TGD populations, notably those on hormone therapy, compared with the cisgender population. It highlights the urgent need for specialized screening and treatment for this vulnerable population, and research into hormone therapy's impact on pain. These insights aim to foster more effective, personalized healthcare, enhancing the well-being and quality of life for the TGD community.

Do patients with fibromyalgia syndrome receive updated management strategies? A web-based survey among Italian physiotherapists

INTRODUCTION

Fibromyalgia syndrome (FMS) causes significant pain, disability, and costs among patients. It is paramount that healthcare professionals have an updated knowledge of its characteristics and Clinical Practice Guidelines (CPGs).

OBJECTIVES

To determine the knowledge, adherence to CPGs, and confidence of Italian physiotherapists in managing patients with FMS, explore barriers to the implementation of CPG' recommendations, compare groups' adherence to CPGs, and determine which variables explained most of the participants' knowledge.

METHODS

The survey was administered via social media and newsletter (i.e., Italian Association of Physiotherapists, AIFI) to Italian practicing physiotherapists. The protocol of this work was prospectively registered in the Open Science Framework.

RESULTS

Total replies were 398. Italian physiotherapists showed a good knowledge of FMS and adherence to CPGs. Ninety-one percent reported a medium or lower confidence in managing patients with FMS. Sixty-seven percent judged their knowledge of CPGs as poor or very poor. The remaining 33% mentioned patients' psychosocial aspects, multidisciplinary relationships, and lack of training on communication strategies as the main barriers to the implementation of CPGs. Being an Orthopaedic Manipulative Physical Therapist (OMPT) resulted in a better adherence to CPGs on 11/14 items. Knowledge scores were correlated (r = 0.244) with being an OMPT (Stand β = 0.123) and years of professional activity (Stand β = -0.126).

CONCLUSIONS

Although Italian physiotherapists demonstrated a good knowledge of FMS and reported a good adherence to CPGs' recommendations, they may still experience barriers to the implementation of evidence-based management strategies.

Prediction models for treatment success after an interdisciplinary multimodal pain treatment program

Chronic musculoskeletal pain (CMP) poses a widespread health and socioeconomic problem, being the most prevalent chronic pain condition. Interdisciplinary multimodal pain treatment (IMPT) is considered the gold standard, offering cost-effective long-term care. Unfortunately, only a subset of patients experiences clinically relevant improvements in pain, fatigue, and disability post-IMPT. Establishing a prediction model encompassing various outcome measures could enhance rehabilitation and personalized healthcare. Thus, the aim was to develop and validate a prediction model for IMPT success in patients with CMP. A prospective cohort study within routine care was performed, including patients with CMP undergoing a 10-week IMPT. Success across four outcome measures was determined: patients' recovery perspective, quality of life (physical and mental), and disability. Sixty-five demographic and candidate predictors (mainly patient reported outcome measures) were examined. Finally, 2309 patients participated, with IMPT success rates ranging from 30% to 57%. Four models incorporating 33 predictors were developed, with treatment control being the sole consistent predictor across all models. Additionally, predictors effects varied in direction in the models. All models demonstrated strong calibration, fair to good discrimination, and were internally validated (optimism-corrected AUC range 0.69-0.80). Our findings show that treatment success can be predicted using standardized patient-reported measures, exhibiting strong discriminatory power. However, predictors vary depending on the outcome, underscoring the importance of selecting the appropriate measure upfront. Clinically, these results suggest potential for patient-centered care and may contribute to the development of a scientifically sound decision tool.

The physical activity paradox; exploring the relationship with pain outcomes. The Tromsø Study 2015-2016

ABSTRACT

Paradoxical associations have been observed for leisure-time physical activity (LTPA) and occupational physical activity (OPA) and several health-related outcomes. Typically, higher LTPA is associated with health benefits and high OPA with health hazards. Using data from the Tromsø Study (2015-2016), we assessed how questionnaire-based LTPA and OPA (n = 21,083) and accelerometer-measured physical activity (PA) (n = 6778) relate to pain outcomes. Leisure-time physical activity and OPA were categorized as inactive PA, low PA, and moderate-to-vigorous PA and then aggregated into 9 levels, eg, inactive LTPA/inactive OPA. Accelerometer-measured PA included counts/minute, steps/day, and WHO PA recommendations from 2010 to 2020. Three binary pain outcomes (any pain, any chronic pain, and moderate-to-severe chronic pain) were constructed based on pain location, intensity, duration, and impact on daily activities. By using Poisson regression to estimate absolute and relative associations, we found that high LTPA was associated with lower pain prevalence and vice versa for OPA. Compared to inactive LTPA, prevalence ratio (PR) with 95% confidence intervals was lowest for moderate-to-vigorous LTPA, 0.93 (0.89-0.96) for any pain, 0.88 (0.84-0.93) for any chronic pain, and 0.66 (0.59-0.75) for moderate-to-severe chronic pain. Compared to sedentary OPA, the ratio was highest for moderate-to-vigorous OPA, 1.04 (1.01-1.07) for any pain, 1.06 (1.02-1.10) for any chronic pain, and 1.33 (1.21-1.46) for moderate-to-severe chronic pain. Aggregated LTPA and OPA showed lower outcomes for moderate-to-vigorous LTPA combined with lower levels of OPA. Higher levels of accelerometer-measured PA were associated with less pain. To summarize, we found inverse associations for LTPA and OPA. Benefits from LTPA seem to depend on low levels of OPA.

Prevalence of Spinal Segmental Sensitization Syndrome in Outpatients Attending Physical Medicine and Rehabilitation Centers for Chronic Musculoskeletal Pain: A Multicenter Study

OBJECTIVE

To determine the prevalence of spinal segmental sensitization (SSS) syndrome, a regional pain disorder, among patients visiting physical medicine and rehabilitation centers (PM&RCs) for chronic musculoskeletal pain (CMSP).

DESIGN

An observational, descriptive, cross-sectional study conducted from March to July 2023.

SETTING

Seven PM&RCs from 5 cities, representing 3 care systems: Social Security (SS), Ministry of Health (MH), and private practice (PP).

PARTICIPANTS

All patients, regardless of age, attending a physiatry consultation for CMSP for the first time and who provided informed consent to participate were included. Nonprobabilistic sampling was employed.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

We estimated the overall prevalence of SSS syndrome as a percentage among patients with CMSP, stratified by health care institution, sex, age, and occupation type. We also recorded the spinal segments involved and any concomitant painful disorders (CPDs). SSS syndrome was diagnosed using standardized criteria.

RESULTS

Of the eligible participants, 319 with CMSP were enrolled; 73.4% were women, and the median age of participants was 56.9 (range, 13-89y) years. The overall prevalence of SSS syndrome was 53.3%. Of these, 69.1%, 42.2%, and 13.8% were in the SS, MH, and PP systems, respectively. The most affected were female participants (56.4%), those aged 50-64 years (60.4%), and those with active jobs (58.8%). Most commonly, the lumbosacral and lumbar segments were affected, followed by the lower and middle cervical levels. Spine pathologies were the most common CPDs.

CONCLUSION

The prevalence of SSS syndrome was high among patients who visited PM&RCs for CMSP and varied according to the care system. Further research on SSS syndrome is warranted to relieve the burden it poses on patients with CMSP and ensure proper diagnosis in clinical practice.

Mental Defeat Predicts Increased Suicide Risk in Chronic Pain: A 12-Month Prospective Study

BACKGROUND

Mental defeat is considered a potential risk factor for suicidal thoughts and behaviours in chronic pain. This study evaluated the role of mental defeat in predicting future suicide risk and examined whether depression influences this relationship.

METHODS

A total of 340 participants with chronic pain completed questionnaires at two time points, 12 months apart. Data collected included sociodemographic and pain characteristics, mental defeat, psychosocial risk factors including depression and health-related variables. Weighted univariate and multivariable analyses assessed the link between mental defeat and suicide risk, with a moderation analysis testing the role of depression.

RESULTS

Higher levels of mental defeat and depression were linked to increased suicide risk at 12 months. Depression significantly amplified the effect of mental defeat on suicide risk, particularly in individuals with higher depression levels (B = 0.06, SE = 0.01, t = 6.21, p < 0.001) compared with moderate (B = 0.05, SE = 0.01, t = 5.20, p < 0.001) or low levels of depression (B = 0.04, SE = 0.01, t = 2.83, p = 0.004), indicating a dose-response relationship.

CONCLUSIONS

Mental defeat is a significant risk factor for suicide in chronic pain, with depression intensifying this risk. Addressing both mental defeat and depression simultaneously in treatment may help reduce suicide risk in these patients.

SIGNIFICANCE

This study strengthens the evidence linking mental defeat with heightened suicide risk in chronic pain. By providing prospective data, it clarifies the temporality of this relationship. Given that suicide risk doubles in chronic pain patients, whereby comorbid depression is common, these findings have crucial clinical implications. Both mental defeat and depression are modifiable. Addressing them together in treatment may help reduce suicide risk in this population.

Exploring the association of metabolic factors and chronic musculoskeletal pain over a period of 10 years - the Doetinchem Cohort Study

OBJECTIVE

To examine (a) the association between metabolic factors and chronic musculoskeletal pain (CMP), (b) metabolic predictors of CMP 10 years later, and (c) the association and evolution of metabolic factors across different CMP trajectory groups.

DESIGN

Data from the longitudinal Doetinchem Cohort Study were used. We used round 4 (2003-2007), with 4519 participants aged 36-75 years, as the baseline for the present study, with follow-up measurements in round 5 (2008-2012), and 6 (2013-2017), including self-reported pain and metabolic factors, which were measured either via self-report or physical assessment. For the three research aims, (a) generalized linear mixed-effects models, (b) binary logistic regression analyses and (c) linear mixed-effects models were used.

RESULTS

(a) Female sex, higher age, presence of diabetes, higher BMI, lower diastolic blood pressure (BP), and elevated cystatin C were significantly associated with CMP in multivariable logistic analyses. (b) Female sex and elevated BMI were predictors of CMP 10 years later. (c) Those pain-free for 10 years had the lowest BMI levels compared to other CMP groups (development, recovery, persistent, and recurrent CMP). BMI was higher in the persistent CMP group than in the development and recovery groups. The pain-free group had higher diastolic BP compared to those in the persistent CMP group. Participants in the persistent CMP group had higher Cystatin C levels than the free, development and recovery CMP groups. Regarding the evolution of metabolic factors over time, BMI, glucose and diastolic BP evolved differently across the CMP trajectory groups.

CONCLUSION

Our findings indicate the importance of metabolic factors, especially BMI, in the onset and progression of CMP. These findings underscore the need to consider metabolic health in the prevention and treatment of CMP. Key Points • Metabolic factors are associated with the presence of chronic musculoskeletal pain. • Female sex and elevated BMI are predictive of musculoskeletal pain (MP) 10 years later. • Metabolic factors evolve differently over time across different pain trajectory groups, with variations in BMI, glucose, and diastolic blood pressure.

Sex differences in the affective-cognitive dimension of neuropathic pain: Insights from the spared nerve injury rat model

Over 40% of neuropathic pain patients experience mood and cognitive disturbances, often showing reduced response to analgesics, with most affected individuals being female. This highlights the critical role of biological sex in pain-related affective and cognitive disorders, making it essential to understand the emotional and cognitive circuits linked to pain for improving treatment strategies. However, research on sex differences in preclinical pain models is lacking. This study aimed to investigate these differences using the spared nerve injury (SNI) rat model, conducting a comprehensive series of behavioural tests over 100 days post-injury to identify key time points for observing sex-specific behaviours indicative of pain-related conditions. The findings revealed that female rats exhibited greater mechanical and cold hypersensitivity compared to males following nerve injury and showed earlier onset of depression-related behaviours, while males were more prone to anxiety, social, and memory-related alterations. Interestingly, by the 14th week post-injury, females displayed no signs of these emotional and cognitive impairments. Additionally, fluctuations in the oestrous cycle or changes in testosterone and oestradiol levels did not correlate with sex differences in pain sensitivity or negative affect. Recognizing the influence of biological sex on pain-induced affective and cognitive alterations, especially in later stages post-injury, is crucial for enhancing our understanding of this complex pain disorder. PERSPECTIVE: This manuscript reports the relevance of long-term investigations of sex differences in chronic pain. It shows differential development of somatosensory sensitivity, negative affective states and cognitive impairments in males and females. It emphasizes the importance of including subjects of both sexes in the investigation of pain-related mechanisms and therapeutic management.

Nociplastic pain in axial spondyloarthritis and psoriatic arthritis: role of JAK kinases in immunopathology and therapeutic impact of JAK inhibitors

INTRODUCTION

Pain in both peripheral and axial joints is a major symptom in patients with psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA). Emerging evidence demonstrates pain mechanisms, beyond those related to inflammation or joint damage, based on aberrant processing of nociceptive stimuli peripherally as well as centrally. The Janus kinase/signal transducers and activators of transcription (JAK-STAT) signaling pathway has been implicated in the processing of pain beyond its role in mediating inflammation and inhibitors of this pathway approved for the treatment of axSpA and PsA have been shown to alleviate a broad array of pain outcomes in both axial and peripheral joints.

AREAS COVERED

We review recent definitions and standardization of the nomenclature for categorizing chronic pain according to causality, assessment tools to evaluate nociplastic pain, the pathophysiologic role of JAK-STAT signaling in nociplastic pain, evidence for the presence of nociplastic pain in axSpA and PsA, and the impact of JAK inhibitors (JAKi) on pain outcomes in clinical trials (PubMed: 01/01/2019-04/01-2024).

EXPERT OPINION

Nociplastic pain assessment has been confined almost entirely to the use of a limited number of questionnaires in cross-sectional studies of these diseases. Though effective for alleviating pain, it is unclear if JAKi specifically impact nociplastic pain.

Abnormal dynamic functional networks during pain-free periods: Resting-state co-activation pattern analysis in primary dysmenorrhea: Abnormal dynamic functional networks in primary dysmenorrhea

Chronic pain alters the configuration of brain functional networks. Primary dysmenorrhea (PDM) is a form of chronic visceral pain, which has been identified spatial alterations in brain functional networks using static functional connectivity analysis methods. However, the dynamics alterations of brain functional networks during pain-free periovulation phase remain unclear. Using the co-activation pattern (CAP) method, we investigated the dynamic network characteristics of brain functional networks and their relationship with pain-related emotions in a sample of 59 women with PDM and 57 demographically matched healthy controls (HCs) during the pain-free periovulation phase. We observed that patients with PDM showed significant alterations in brain dynamics compared to HCs in the slow-4 (0.027-0.073 Hz) frequency band during the pain-free periovulation phase. Additionally, the fraction of time for CAP state 2 was positively correlated with the Pain Catastrophizing Scale-helplessness score, while the persistence time for CAP state 1 was positively correlated with the McGill Pain Questionnaire score. Our results provide new insights, suggesting that the atypical brain functional network dynamics may serve as a potential biological marker of patients with PDM during the pain-free periovulation phase.