Survey criteria for fibromyalgia independently predict increased postoperative opioid consumption after lower-extremity joint arthroplasty: a prospective, observational cohort study

Unintended Prolonged Opioid Use: Protocol for a Case-Controlled Trial

BACKGROUND

Misuse of prescription opioids remains a public health problem. Appropriate short-term use of these medications in opioid-naive patients is indicated in selected settings but can result in unintended prolonged opioid use (UPOU), defined as the continuation of opioid therapy beyond the period by which acute pain would have been expected to resolve. Clinical strategies aimed at preventing UPOU are lacking due to the absence of information about how this poorly understood clinical phenomenon actually develops.

OBJECTIVE

In this research project, 3 Clinical and Translational Science Awards (CTSA) programs (Mayo Clinic, University of Michigan, and Yale University) leveraged the conceptual framework for UPOU to investigate how patient characteristics, practice environment characteristics, and opioid prescriber characteristics facilitate or impede UPOU. All data management and analyses were conducted at a fourth CTSA program (University of Minnesota). This work was accomplished by pursuing 3 specific aims.

METHODS

In aim 1, opioid-naive adults receiving an initial opioid prescription were recruited for study participation. Opioid prescriptions were identified longitudinally, and patterns of use were categorized as short-term, episodic, or long-term use using established criteria. Using a prospective case-control design, patients progressing to UPOU were matched 1:1 with patients who did not develop UPOU, and differences in patient characteristics were assessed. In aim 2, clinicians who prescribed opioids to patients in aim 1 were identified and recruited for prospective assessments. Institutional and individual practice environments were assessed using a validated self-report survey. In aim 3, structural equation modeling was used to evaluate data collected in aims 1 and 2, and identified interactions were further evaluated in a large national administrative claims database.

RESULTS

Patient recruitment began on August 1, 2019. However, due to the COVID-19 pandemic, patient recruitment was slowed and intermittently interrupted over the ensuing 3-year period. As a result of regional variations in the impact of the COVID-19 pandemic on research activities, the majority of patient and clinician recruitment occurred at the Mayo Clinic site.

CONCLUSIONS

Following complete data analyses, it is anticipated that electronic health record systems will be leveraged to help clinicians identify at risk patients and to develop direct-to-patient educational materials to raise awareness of the risk factors for developing UPOU.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04024397; https://clinicaltrials.gov/study/NCT04024397.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/72032.

Predicting Extent of Opioid Use Following Cardiac Surgery: A Pilot Study

OBJECTIVES

This study was designed to test whether a negative affect phenotype reflecting depression, anxiety, anger, and pain catastrophizing predicts inpatient and outpatient opioid use outcomes following cardiac surgery.

DESIGN

In a single-center prospective observational pilot study, the authors obtained validated measures of negative affect and opioid-related phenotype preoperatively and collected opioid use and opioid misuse-related outcomes at 30-day postoperative follow-up.

SETTING

Quaternary medical center.

PARTICIPANTS

The final dataset included 30 adult patients undergoing elective cardiac surgery procedures between August 19, 2022, and August 29, 2023.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Opioid outcomes included: (1) total inpatient postoperative opioid use (in milligram morphine equivalents), (2) self-reported number of days that prescribed outpatient opioids were used during the 30-day follow-up period (Timeline Followback method), and (3) number of opioid misuse-related behaviors (Current Opioid Misuse Measure-9) at 30-day follow-up. Generalized linear model analyses using a Poisson distribution indicated that greater preoperative depression, anxiety, anger, pain catastrophizing, and opioid misuse risk (indexed by the Screener and Opioid Assessment for Patients with Pain- Revised) were all significantly (p < 0.002) associated with greater inpatient and outpatient postoperative opioid use, as well as more opioid misuse-related behaviors at 30-day follow-up (p < 0.001).

CONCLUSIONS

Patients with higher preoperative levels of negative affect (depression, anxiety, anger, and pain catastrophizing) use more inpatient and outpatient opioid analgesics following cardiac surgery, a pattern similar to noncardiac surgery populations. Results support further study of patient-specific approaches to opioid prescribing to reduce the risk for opioid use disorder post-cardiac surgery.

Central sensitization in alcohol use disorder: correlates of pain, addiction and health-related quality of life

BACKGROUND

Central sensitization is an important mechanism underlying many chronic pain conditions. Chronic pain and alcohol use disorder (AUD) are highly comorbid. Despite great scientific interest in brain mechanisms linking chronic pain and AUD, progress has been impeded by difficulty assessing central sensitization in AUD.

OBJECTIVE

The present study is the first to employ a validated surrogate measure to describe central sensitization in a clinical sample with AUD.

METHODS

Participants with AUD (n = 99) were recruited from an academic addiction treatment center. A well-established surrogate measure of central sensitization, The American College of Rheumatology Fibromyalgia Survey Criteria (ACRFMS) was administered. Participants also responded to questions about quality of life (RAND-36), and AUD. Descriptive analyses and Spearman's rho correlations were performed.

RESULTS

Chronic pain and evidence of central sensitization were prevalent. Greater central sensitization was associated with worse health-related quality of life. Participants higher in central sensitization expressed greater endorsement of pain as a reason for AUD onset, maintenance, escalation, treatment delay, and relapse.

CONCLUSION

The present study bolsters prior assertions that AUD and chronic pain might compound one another via progressive sensitization of shared brain circuitry. These results may inform future mechanistic research and precision AUD treatment.

Fibromyalgia is associated with increased odds of prior pain-precipitated relapse among non-treatment-seeking individuals with opioid use disorder

BACKGROUND/OBJECTIVES

Chronic pain is an opioid use disorder (OUD) treatment barrier and associated with poor outcomes in OUD treatment including relapse. Fibromyalgia is a chronic pain condition related to central nervous system substrates that overlap with the brain disease model of OUD. We know of no studies that have looked at non-treatment seeking individuals, to see if fibromyalgia might represent a barrier to OUD treatment. Given many non-treatment-seeking individuals previously attempted recovery before experiencing relapse, and chronic pain is a known precipitant of relapse, fibromyalgia might be a currently unappreciated modifiable factor in OUD relapse and, potentially, a barrier to treatment reengagement among those not currently seeking treatment. This study aimed to determine if fibromyalgia is associated with greater odds of agreeing that 'I have tried to stop using opioids before, but pain caused me to relapse' among non-treatment seeking individuals with OUD.

METHODS

This cross-sectional study recruited non-treatment-seeking individuals with OUD (n = 141) from a syringe service program. Ordinal logistic regression was used to determine if the presence of fibromyalgia increased the odds of agreement with prior pain-precipitated relapse.

RESULTS

Fibromyalgia was identified in 35% of study participants and associated with 125% greater odds of strongly agreeing that pain had previously caused them to relapse, even after accounting for relevant covariates, including age, sex, depression, anxiety, OUD severity, and pain severity.

CONCLUSIONS

This study provides early evidence that the presence of fibromyalgia may be associated with increased odds of pain-precipitated OUD relapse.

Risk Factors for Increased Opioid Use During Postoperative Intensive Care

IMPORTANCE

In the ICU, opioids treat pain and improve ventilator tolerance as part of an analgosedation approach. Identifying predictors of opioid consumption during the ICU course might highlight actionable items to reduce opioid consumption.

OBJECTIVES

To identify risk factors for opioid use during a postoperative ICU course.

DESIGN, SETTING, AND PARTICIPANTS

Patients enrolled in the Michigan Genomics Initiative single-center prospective observational cohort study completed baseline preoperative sociodemographic and mental/physical health questionnaires and provided blood samples for genetic analysis. Included patients were 18 years old and older, admitted to ICU postoperatively, and received opioids postoperatively.

MAIN OUTCOMES AND MEASURES

The primary outcome was ICU mean daily oral morphine equivalent (OME) use. The association between OME and phenotypic risk factors and genetic variants previously associated with pain were analyzed through univariable and multivariable linear regression models.

RESULTS

The cohort consisted of 1865 mixed-surgical patients with mean age of 56 years (sd, 15 yr). Preoperative opioid users were more likely to continue to receive opioids throughout their ICU stay than opioid-naive patients. OME (log10 scale) was most strongly associated with ICU mechanical ventilation (β = 0.27; 95% CI, 0.15-0.38; p < 0.0001; effect size 1.85 for receiving > 24 hours of mechanical ventilation), preoperative opioid use (β = 0.22; 95% CI, 0.16-0.29; p < 0.0001; effect size 1.67 for receiving preoperative opioids), major surgery (β = 0.21; 95% CI, 0.12-0.30; p < 0.0001; effect size 1.62 compared with minor surgery), and current/former illicit drug use (β = 0.12; 95% CI, 0.01-0.23; p = 0.04; effect size 1.30 for drug use). Younger age, centralized pain, and longer anesthetic duration were also significantly associated with OME but with smaller effect sizes. Selected genetic variants (FKBP5, COMT, and OPRM1) were not associated with OME use.

CONCLUSIONS AND RELEVANCE

Mechanical ventilation and preoperative opioids were the strongest risk factors for postoperative ICU opioid consumption, whereas psychologic factors and genetic variants were not associated.

From fibrositis to fibromyalgia to nociplastic pain: how rheumatology helped get us here and where do we go from here?

Rheumatologists and rheumatology have had a prominent role in the conceptualisation of nociplastic pain since the prototypical nociplastic pain condition is fibromyalgia. Fibromyalgia had been previously known as fibrositis, until it became clear that this condition could be differentiatied from autoimmune disorders because of a lack of systemic inflammation and tissue damage. Nociplastic pain is now thought to be a third descriptor/mechanism of pain, in addition to nociceptive pain (pain due to peripheral damage or inflammation) and neuropathic pain. Nociplastic pain can occur in isolation, or as a co-morbidity with other mechanisms of pain, as commonly occurs in individuals with autoimmune disorders. We now know that the cardinal symptoms of nociplastic pain are widespread pain (or pain in areas not without evidence of inflammation/damage), accompanied by fatigue, sleep and memory issues. There is objective evidence of amplification/augmentation of pain, as well as of non-painful stimuli such as the brightness of lights and unpleasantness of sound or odors. Nociplastic pain states can be triggered by a variety of stressors such as trauma, infections and chronic stressors. Together these features suggest that the central nervous system (CNS) is playing a major role in causing and maintaining nociplastic pain, but these CNS factors may in some be driven by ongoing peripheral nociceptive input. The most effective drug therapies for nociplastic pain are non-opioid centrally acting analgesics such as tricyclics, serotonin-norepinephrine reuptake inhibitors and gabapentinoids. However the mainstay of therapy of nociplastic pain is the use of a variety of non-pharmacological integrative therapies, especially those which improve activity/exercise, sleep and address psychological co-morbidities.

Hierarchical Clustering Applied to Chronic Pain Drawings Identifies Undiagnosed Fibromyalgia: Implications for Busy Clinical Practice

Currently-used assessments for fibromyalgia require clinicians to suspect a fibromyalgia diagnosis, a process susceptible to unintentional bias. Automated assessments of standard patient-reported outcomes (PROs) could be used to prompt formal assessments, potentially reducing bias. We sought to determine whether hierarchical clustering of patient-reported pain distribution on digital body map drawings predicted fibromyalgia diagnosis. Using an observational cohort from the University of Pittsburgh's Patient Outcomes Repository for Treatment registry, which contains PROs and electronic medical record data from 21,423 patients (March 17, 2016-June 25, 2019) presenting to pain management clinics, we tested the hypothesis that hierarchical clustering subgroup was associated with fibromyalgia diagnosis, as determined by ICD-10 code. Logistic regression revealed a significant relationship between the body map cluster subgroup and fibromyalgia diagnosis. The cluster subgroup with the most body areas selected was the most likely to receive a diagnosis of fibromyalgia when controlling for age, gender, anxiety, and depression. Despite this, more than two-thirds of patients in this cluster lacked a clinical fibromyalgia diagnosis. In an exploratory analysis to better understand this apparent underdiagnosis, we developed and applied proxies of fibromyalgia diagnostic criteria. We found that proxy diagnoses were more common than ICD-10 diagnoses, which may be due to less frequent clinical fibromyalgia diagnosis in men. Overall, we find evidence of fibromyalgia underdiagnosis, likely due to gender bias. Coupling PROs that take seconds to complete, such as a digital pain body map, with machine learning is a promising strategy to reduce bias in fibromyalgia diagnosis and improve patient outcomes. PERSPECTIVE: This investigation applies hierarchical clustering to patient-reported, digital pain body maps, finding an association between body map responses and clinical fibromyalgia diagnosis. Rapid, computer-assisted interpretation of pain body maps would be clinically useful in prompting more detailed assessments for fibromyalgia, potentially reducing gender bias.

Deciphering nociplastic pain: clinical features, risk factors and potential mechanisms

Nociplastic pain is a mechanistic term used to describe pain that arises or is sustained by altered nociception, despite the absence of tissue damage. Although nociplastic pain has distinct pathophysiology from nociceptive and neuropathic pain, these pain mechanisms often coincide within individuals, which contributes to the intractability of chronic pain. Key symptoms of nociplastic pain include pain in multiple body regions, fatigue, sleep disturbances, cognitive dysfunction, depression and anxiety. Individuals with nociplastic pain are often diffusely tender - indicative of hyperalgesia and/or allodynia - and are often more sensitive than others to non-painful sensory stimuli such as lights, odours and noises. This Review summarizes the risk factors, clinical presentation and treatment of nociplastic pain, and describes how alterations in brain function and structure, immune processing and peripheral factors might contribute to the nociplastic pain phenotype. This article concludes with a discussion of two proposed subtypes of nociplastic pain that reflect distinct neurobiological features and treatment responsivity.

Nociplastic Pain and Pain-Motivated Drinking in Alcohol Use Disorder

Heavy chronic alcohol use may produce pain amplification through neurochemical and neuroplastic changes at multiple levels of the nervous system. Similar changes are thought to underlie nociplastic pain. The American College of Rheumatology Fibromyalgia Survey has been used as a surrogate for nociplastic pain, including among individuals with alcohol use disorder (AUD). However, studies linking nociplastic pain to pain-motivated drinking are lacking. The present study aimed to determine if nociplastic pain is associated with pain-motivated drinking in AUD. To achieve this aim, a new scale-the Pain-Motivated Drinking Scale (PMDS)-was developed to measure how often participants were motivated by pain to drink alcohol. Measurement properties of this new scale were determined, including its factor structure, internal consistency reliability, and construct validity. In this cross-sectional observational study, participants with AUD (n = 138) were consecutively recruited from the patient pool at an academic addiction treatment facility. Seventy-two percent (95, 72.0%) reported they drank alcohol "to get relief from physical pain" at least some of the time, and over forty-two percent (56, 42.4%) reported pain relief motivated their drinking at least half of the time. PMDS had a single-factor structure, strong internal consistency reliability, and construct validity. A multiple hierarchical linear regression was run to determine if nociplastic pain was associated with pain-motivated drinking. Nociplastic pain was associated with PMDS even after controlling for potential confounders and pain severity. These findings suggest nociplastic pain is uniquely associated with pain-motivated drinking in AUD. PERSPECTIVE: Nociplastic pain is independently associated with pain-motivated drinking in alcohol use disorder (AUD). The Pain-Motivated Drinking Scale (PMDS) is a new scale to measure how often people drink to cope with pain. PMDS has promising psychometric properties. Nociplastic pain may be uniquely associated with pain-motivated drinking in AUD.

Questionnaires for the Assessment of Central Sensitization in Endometriosis: What Is the Available Evidence? A Systematic Review with a Narrative Synthesis

It has been suggested that central sensitization (CS) may be involved in the failure of standard medical and surgical treatment to relieve endometriosis-related pain. However, there is no gold standard for the diagnosis of CS, and self-reported questionnaires are used as diagnostic surrogates. The main objective of this review was to identify all CS questionnaires used in clinical endometriosis studies. The secondary objective was to qualitatively analyze strengths and weaknesses of each questionnaire. A PubMed and EMBASE systematic literature search conducted in April 2023 using the terms "endometriosis; central pain; central sensitization; questionnaire; patient-reported outcome measure; screening tool" identified 122 publications: six articles were included in the review. The Central Sensitization Inventory (CSI) is the most frequently used questionnaire for the detection of CS in patients with endometriosis. It has been validated in patients with endometriosis, in whom it appears to have good psychometric proprieties. The Fibromyalgia Survey Questionnaire (FSQ) has also been used, although it has not been specifically validated in endometriosis patients. The debate regarding these questionnaires' construct validity is still open and will be so until a gold standard diagnostic tool for CS is found. In fact, some authors argue these questionnaires are measuring psychological vulnerability and a hypervigilant state that is associated with pain, rather than CS itself. However, their use should not be discouraged as they are able to identify chronic pain patients which warrant further attention and who may benefit from broader treatment strategies.

Risk Factors for Rescue Opioid Prescription After Cubital Tunnel Surgery

BACKGROUND

Concerns regarding the ongoing opioid epidemic have led to heightened scrutiny of postoperative opioid prescribing patterns for common orthopedic surgical procedures. This study investigated patient- and procedure-specific risk factors for additional postoperative opioid rescue prescriptions following ambulatory cubital tunnel surgery.

METHODS

A retrospective review was performed of patients who underwent cubital tunnel surgery at 2 academic medical centers between June 1, 2015 and March 1, 2020. Patient demographics, comorbidities, prior opioid history, and surgical variables were recorded. The primary outcome was postoperative rescue opioid prescription. Univariate and bivariate statistical analyses were performed.

RESULTS

Two hundred seventy-four patients were included, of whom 171 (62%) underwent in situ ulnar nerve decompression and 103 (38%) underwent ulnar nerve decompression with anterior transposition. The median postoperative opioid prescription amount was 90 morphine equivalent units (MEU) for the total cohort, 77.5 MEU for in situ ulnar nerve decompression, and 112.5 MEU for ulnar nerve decompression with transposition. Twenty-two patients (8%) required additional rescue opioid prescriptions postoperatively. Female sex, fibromyalgia, chronic opioid use, chronic pain diagnosis, and recent opioid were associated with the need for additional postoperative rescue opioid prescriptions.

CONCLUSIONS

While most patients do not require additional rescue opioid prescriptions after cubital tunnel surgery, chronic pain patients and patients with pain sensitivity syndromes are at risk for requiring additional rescue opioid prescriptions. For these high-risk patients, preoperative collaboration of a multidisciplinary team may be beneficial for developing a perioperative pain management plan that is both safe and effective.

Functional somatic syndromes are associated with inferior outcomes and increased complications after hip and knee arthroplasty: a systematic review

BACKGROUND

Functional somatic syndromes (FSSs), defined as chronic physical symptoms with no identifiable organic cause, may impact results after hip and knee arthroplasty. The purpose of this study was to perform a systematic review assessing the relationship between FSSs and clinical outcomes after primary total hip arthroplasty (THA), total knee arthroplasty (TKA), and unicompartmental knee arthroplasty (UKA).

METHODS

The PubMed and Web of Science databases were queried from January 1955 through December 2021 for studies investigating the impact of at least one FSS (fibromyalgia, irritable bowel syndrome (IBS), chronic headaches, and chronic low back pain) on outcomes after primary THA/TKA/UKA. Outcomes of interest included patient-reported outcome measures (PROMs), postoperative opioid use, complications, revisions, and costs of care.

RESULTS

There were twenty-eight studies, including 768,909 patients, of which 378,384 had an FSS. Five studies reported preoperative PROMs prior to THA/TKA, all of which showed worse PROMs among patients with at least 1 FSS diagnosis. Thirteen studies reported postoperative PROMs after THA/TKA, all of which demonstrated worse PROMs among patients with at least 1 FSS diagnosis. Patients with FSS diagnoses were more likely to continue using opioids at 3, 6, and 12 months following TKA, THA, and UKA. Medical and surgical complications, as well as revision rates, were higher among patients with FSSs.

CONCLUSION

Patients with FSSs have inferior PROMs and are at increased risk for prolonged postoperative opioid use, medical and surgical complications, and revision after hip and knee arthroplasty. Improved understanding of the factors influencing the success of hip and knee arthroplasty is critical. Future studies should address the biopsychosocial determinants of health that can impact outcomes after total joint arthroplasty.

Thalamic neurometabolite alterations in chronic low back pain: a common phenomenon across musculoskeletal pain conditions?

ABSTRACT

Recently, we showed that patients with knee osteoarthritis (KOA) demonstrate alterations in the thalamic concentrations of several metabolites compared with healthy controls: higher myo-inositol (mIns), lower N-acetylaspartate (NAA), and lower choline (Cho). Here, we evaluated whether these metabolite alterations are specific to KOA or could also be observed in patients with a different musculoskeletal condition, such as chronic low back pain (cLBP). Thirty-six patients with cLBP and 20 healthy controls were scanned using 1 H-magnetic resonance spectroscopy (MRS) and a PRESS (Point RESolved Spectroscopy) sequence with voxel placement in the left thalamus. Compared with healthy controls, patients with cLBP demonstrated lower absolute concentrations of NAA ( P = 0.0005) and Cho ( P < 0.05) and higher absolute concentrations of mIns ( P = 0.01) when controlling for age, as predicted by our previous work in KOA. In contrast to our KOA study, mIns levels in this population did not significantly correlate with pain measures (eg, pain severity or duration). However, exploratory analyses revealed that NAA levels in patients were negatively correlated with the severity of sleep disturbance ( P < 0.01), which was higher in patients compared with healthy controls ( P < 0.001). Additionally, also in patients, both Cho and mIns levels were positively correlated with age ( P < 0.01 and P < 0.05, respectively). Altogether, these results suggest that thalamic metabolite changes may be common across etiologically different musculoskeletal chronic pain conditions, including cLBP and KOA, and may relate to symptoms often comorbid with chronic pain, such as sleep disturbance. The functional and clinical significance of these brain changes remains to be fully understood.

Relationship Between Nociplastic Pain Involvement and Medication Use, Symptom Relief, and Adverse Effects Among People Using Medical Cannabis for Chronic Pain

OBJECTIVES

Cannabis is increasingly being used for chronic pain management, but cannabis' effects remain poorly characterized in chronic nociplastic pain (NPP), which is posited to be caused by disturbances in nervous system pain processing. In this cross-sectional study (n=1213), we used the 2011 Fibromyalgia (FM) Survey Criteria as a surrogate measure for degree of NPP among individuals using medical cannabis for chronic pain.

METHODS

Using a quartile-split, we investigated associations between the degree of NPP and medication use, cannabis use characteristics, and symptom relief. Continuous variables were assessed using one-way analysis of variance and categorical variables with Pearson χ 2 test and binomial logistic regression for calculation of odds ratios.

RESULTS

Participants were predominately female (59%), with a mean ± SD age of 49.4±13.6 years. Higher FM scores were associated with less self-reported improvement in pain and health since initiating medical cannabis use, as well as more cannabis-related side effects. Paradoxically, higher FM scores were also associated with higher usage of concomitant medication use (including opioids and benzodiazepines) but also with substituting cannabis for significantly more medication classes, including opioids and benzodiazepines.

DISCUSSION

This article presents evidence that individuals in higher NPP quartiles have higher analgesic intake, higher odds of substituting cannabis for medications, higher side effect burden, and lower therapeutic effect from cannabis. These seemingly contradictory findings may reflect higher symptom burden, polypharmacy at baseline, or that NPP may be challenging to treat with cannabis. Further research is necessary to further explain cannabinoid effects in NPP.

Efficacy of aquatic exercise in chronic musculoskeletal disorders: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Aquatic exercise (AE) is becoming ever more popular as a physical therapy, while it is unclear what precise improvements it will produce and how effective it will be in comparison with other non-surgical therapies. The study aimed to assess whether AE positively impacts chronic musculoskeletal disorder patients in terms of pain, physical function, and quality of life.

METHODS

PRISMA guidelines were followed, and our study protocol was published online at PROSPERO under registration number CRD42023417411. We searched PubMed, Embase, Web of Science, and Cochrane library databases for English-language articles published before April 11, 2023, including studies from all relevant randomized controlled trials (RCTs). After screening, we ultimately included 32 RCTs with a total of 2,200 participants. We also performed subgroup analyses for all included studies. This meta-analysis calculated standardized mean difference (SMD) with 95% confidence interval (CI), and the variance was estimated using a random-effects model. The quality of the included studies was assessed by using the Cochrane collaborative "risk of bias" assessment tool (version 2.0). Thus ensuring that the literature included is of high quality.

RESULTS

This meta-analysis included 32 trials with 2,200 participants; these patients were all between the ages of 38-80. The study showed that compared to the no exercise (NE) group, patients in the AE group experienced a remarkable reduction in pain (SMD: -0.64, P < 0.001), a significant increase in physical function (SMD: 0.62, P < 0.001), and a statistically significant improvement in quality of life (SMD: -0.64, P < 0.001). When compared to land-based exercise (LE), AE significantly relieves patients' pain (SMD: -0.35, P = 0.03).

CONCLUSIONS

This is the first systematic review and meta-analysis to study whether AE could improve chronic musculoskeletal disorders. The evidence suggests that AE benefits pain, physical function, and quality of life in adults with chronic musculoskeletal conditions compared to NE. Furthermore, when compared to LE, AE continues to provide a better improvement in patient pain. More long-term clinical trials are needed to confirm AE's positive effects and improvement mechanisms and the more existential advantages compared to LE.

Modifiable physical and behavioural factors associated with widespread pain in older adults with radiographic evidence of knee osteoarthritis

OBJECTIVE

To identify modifiable physical and behavioural factors associated with widespread pain (WSP) in older adults with radiographic evidence of knee osteoarthritis (OA).

METHODS

Cross-sectional initial visit data of participants with radiographic knee OA (Kellgren-Lawrence grade of ≥2) from the Osteoarthritis Initiative Study were analysed. WSP was defined as pain on both sides of the body, above and below the waist, and in the axial skeleton. Time (hrs/d) spent participating in sitting and moderate-strenuous physical activities were calculated from the Physical Activity Scale for the Elderly questionnaire. Physical function was quantified using gait speed and the chair stand test. Restless sleep was assessed using an item on the CES-D Scale. Logistic regression models were constructed to examine the strength of the associations between primary exposures and WSP in unadjusted and adjusted analyses.

RESULTS

Among the 2637 participants (mean age 62.6 years, 58.6% female), 16.8% met the criteria for WSP. All primary measures of interest were related to WSP in unadjusted analyses. In adjusted multivariable analysis, slow gait speed (adjusted odds ratio [aOR] 1.43; 95% CI 1.01, 2.02), lower chair stand rate (aOR 0.98; 95% CI 0.97-0.99), and restless sleep (aOR 1.61; 95% CI 1.25-2.08) maintained significant associations with WSP.

CONCLUSION

Poor sleep behaviours and low physical function capacity are associated with WSP in adults with radiographic knee OA. These findings highlight the importance of assessing sleep, physical function, and pain distribution in this population. Interventions to improve physical function and sleep behaviours should be investigated as potential strategies to mitigate WSP.

Development and prospective validation of postoperative pain prediction from preoperative EHR data using attention-based set embeddings

Preoperative knowledge of expected postoperative pain can help guide perioperative pain management and focus interventions on patients with the greatest risk of acute pain. However, current methods for predicting postoperative pain require patient and clinician input or laborious manual chart review and often do not achieve sufficient performance. We use routinely collected electronic health record data from a multicenter dataset of 234,274 adult non-cardiac surgical patients to develop a machine learning method which predicts maximum pain scores on the day of surgery and four subsequent days and validate this method in a prospective cohort. Our method, POPS, is fully automated and relies only on data available prior to surgery, allowing application in all patients scheduled for or considering surgery. Here we report that POPS achieves state-of-the-art performance and outperforms clinician predictions on all postoperative days when predicting maximum pain on the 0-10 NRS in prospective validation, though with degraded calibration. POPS is interpretable, identifying comorbidities that significantly contribute to postoperative pain based on patient-specific context, which can assist clinicians in mitigating cases of acute pain.

Quantitative Sensory Testing to Characterize Sensory Changes in Hidradenitis Suppurativa Skin Lesions

Importance

Pain is the most impactful symptom in patients with hidradenitis suppurativa (HS). Characterization of sensory profiles may improve understanding of pain mechanisms in HS and facilitate identification of effective pain management strategies.

Objective

To characterize somatosensory profiles in patients with HS at clinically affected and nonaffected sites compared with pain-free reference data.

Design, Setting, and Participants

This cross-sectional study was conducted at the Emory University Dermatology Clinic. It was hypothesized (1) that patients with HS would demonstrate hypersensitivity to pain in HS lesions and (2) that some patients would have sensory profiles consistent with complex pain mechanisms. Therefore, adults with dermatologist-diagnosed HS and at least 1 painful HS lesion at the time of testing were enrolled between September 10, 2020, and March 21, 2022. Patients with other diagnoses contributing to pain or neuropathy were excluded. Data analysis was conducted between March and April 2022.

Exposure

Quantitative sensory testing was performed on HS lesions and control skin according to a standardized protocol.

Main Outcomes and Measures

Quantitative sensory testing outcomes included innocuous thermal and mechanical sensitivity (cold, warmth, and light touch detection thresholds), noxious thermal and mechanical sensitivity (cold, heat, pinprick, and deep pressure pain thresholds and suprathreshold pinprick sensitivity), temporal summation of pinprick, paradoxical thermal sensations, and dynamic mechanical allodynia (pain upon light stroking of the skin). Sensitivity in HS lesions was compared with sensitivity in a control location (the hand) and in pain-free controls using t tests.

Results

This study included 20 participants with a median age of 35.5 (IQR, 30.0-46.5) years, the majority of whom were women (15 [75%]). In terms of race and ethnicity, 2 participants (10%) self-identified as Asian, 11 (55%) as Black, 6 (30%) as White, and 1 (5%) as more than 1 race or ethnicity. Compared with site-specific reference values from healthy, pain-free control participants, HS lesions were insensitive to innocuous cold and warmth, noxious heat, and light touch (t = -5.69, -10.20, -3.84, and 4.46, respectively; all P < .001). In contrast, HS lesions also demonstrated significant hypersensitivity to deep pressure pain (t = 8.36; P < .001) and cutaneous pinprick (t = 2.07; P = .046). Hypersensitivity to deep pressure pain was also observed in the control site (t = 5.85; P < .001). A subset of patients with HS displayed changes in pain processing that are often seen in neuropathic and nociplastic pain conditions, including hypersensitivity to repetitive pinprick (5 [26%]), paradoxical thermal sensations (3 [15%]), and pain upon light stroking of the skin (10 [50%]).

Conclusions and Relevance

The findings of this cross-sectional study suggest that HS involves local changes in the skin or its free nerve endings, possibly leading to peripheral neuropathy and alterations in the transduction of innocuous and noxious thermal and mechanical stimuli. For some patients, central nervous system changes in somatosensory processing may also occur, but confirmatory evidence is needed. Better understanding of neuropathic and nociplastic mechanisms in HS pain could lead to individually tailored treatments.

The current status of fibromyalgia in Korea: an electronic population health data study in Korea

Background

Fibromyalgia (FM) is a complex disorder characterized by widespread chronic pain and tenderness in the muscles, ligaments, and soft tissues. It is a chronic pain condition often accompanied by other symptoms and comorbidities. To effectively manage FM, it is crucial to obtain fundamental epidemiological data pertaining to the target population. Therefore, this study was conducted to elucidate the epidemiological characteristics of FM in the Korean population.

Methods

Population-based medical data of 51,276,314 subscribers to the National Health Insurance Service of Korea from 2014 to 2018 were used in this study.

Results

The overall incidence of FM ranged from 441 (2014) to 541 (2018) cases per 100,000 person-years, with a higher prevalence observed among female patients compared to male patients. The incidence gradually increased until middle age, followed by a decrease. The highest incidence rates were observed in the fifth decade of life for females and the sixth decade of life for males. When categorizing the affected parts of the body, the shoulder region was observed to be the most frequently affected. A comparison of the drug prescriptions based on medical specialty showed that antidepressants were the most commonly prescribed medications. The management of FM leads to consistent increases in medical expenses, regional disparities, and variations in prescription patterns across different medical specialties.

Conclusions

The findings of this study will not only contribute to the understanding of FM characteristics but also provide a vital foundation for efficient management of FM in Korea.

Fibromyalgia predicts increased odds of pain-related addiction exacerbation among individuals with pain and opioid use disorder

ABSTRACT

Fibromyalgia and opioid use disorder (OUD) are highly impactful chronic illnesses with substantially overlapping psychosocial, biological, and clinical features. Little previous research has examined interactions between fibromyalgia and OUD. Limiting such research has been the previous requirement of a clinical examination to diagnose fibromyalgia. The 2011 American College of Rheumatology Fibromyalgia Survey (ACR-FMS) is a validated self-report instrument with high sensitivity and specificity for fibromyalgia intended to enable fibromyalgia research in settings where a clinical examination is impractical. The present observational study uses the ACR-FMS to determine whether fibromyalgia affects odds of acknowledging pain-related OUD exacerbations among a sample of participants with pain and OUD. Participants with pain and OUD (n = 125) were recruited from an academic substance use treatment facility. The ACR-FMS, along with an original scale measuring pain-related OUD exacerbation-the Pain-related OUD Exacerbation Scale-was administered through an electronic survey. The factor structure, internal consistency, and construct validity of Pain-related OUD Exacerbation Scale were tested. In addition, descriptive analyses, multiple hierarchical linear regression, ordinal logistic regression, and multinomial logistic regression analyses were performed. Although all participants had pain, those with fibromyalgia demonstrated significantly greater odds of acknowledging pain-related OUD exacerbations. Pain-related OUD Exacerbation Scale was found to have a single-factor solution, strong internal consistency, and construct validity. This study provides first evidence of fibromyalgia as a risk factor for pain-related exacerbation of OUD and introduces a new scale with promising psychometric properties to measure pain-related OUD exacerbation.

Adolescents and Young Adults With Sickle Cell Disease: Nociplastic Pain and Pain Catastrophizing as Predictors of Pain Interference and Opioid Consumption

OBJECTIVES

Some patients with sickle cell disease (SCD) have features of nociplastic pain. While research suggests that many patients with nociplastic pain consume more opioids due to opioid nonresponsiveness, little is known about the impact of nociplastic pain and pain catastrophizing on opioid consumption and pain interference among adolescents and young adults (AYA) with SCD. The purpose of this study was to (1) characterize nociplastic pain and pain catastrophizing among AYA with SCD, and (2) determine whether these characterizations are associated with subsequent opioid consumption and pain interference 1 month after characterization.

METHODS

Participants completed surveys characterizing nociplastic pain and catastrophizing at a routine clinic visit (baseline). Thereafter, participants received weekly text messages that included pain interference and opioid consumption surveys. Multipredictor 2-part models were used to evaluate the predictive relationships between baseline characterizations and subsequent pain interference, and opioid consumption.

RESULTS

Forty-eight AYA aged 14 to 35 completed baseline measures. Twenty-five percent of participants had scores suggestive of nociplastic pain. Greater nociplastic pain features significantly increased the odds of consuming opioids (odds ratio=1.2) and having greater interference from pain (odds ratio=1.46). Regression analyses found that greater baseline nociplastic pain characteristics were significantly associated with opioid consumption (β=0.13) and pain interference (β=0.061); whereas higher pain catastrophizing scores predicted less opioid consumption (β=-0.03) and less pain interference (β=-0.0007).

DISCUSSION

In this sample of AYA with SCD, features of nociplastic pain predicted higher subsequent opioid consumption and pain interference. Being aware of nociplastic pain features in patients with SCD may better guide individualized pain management.

Identifying Persistent Opioid Use After Surgery: The Reliability of Pharmacy Dispensation Databases

OBJECTIVE

The present study assessed concordance in perioperative opioid fulfillment data between Michigan's prescription drug monitoring program (PDMP) and a national pharmacy prescription database.

BACKGROUND

PDMPs and pharmacy dispensation databases are widely utilized, yet no research has compared their opioid fulfilment data postoperatively.

METHODS

This retrospective study included participants (N=19,823) from 2 registry studies at Michigan Medicine between July 1, 2016, and February 7, 2019. We assessed the concordance of opioid prescription fulfilment between the Michigan PDMP and a national pharmacy prescription database (Surescripts). The primary outcome was concordance of opioid fill data in the 91 to 180 days after surgical discharge, a time period frequently used to define persistent opioid use. Secondary outcomes included concordance of opioid dose and number of prescriptions fulfilled. Multinomial logistic regression analysis examined concordance across key subgroups.

RESULTS

In total, 3076 participants had ≥1 opioid fulfillments 91 to 180 days after discharge, with 1489 (49%) documented in PDMP only, 243 (8%) in Surescripts only, and 1332 (43%) in both databases. Among participants with fulfillments in both databases, there were differences in the number (n=239; 18%) and dose (n=227; 17%). The PDMP database was more likely to capture fulfillment among younger and publicly insured participants, while Surescripts was more likely to capture fulfillment from counties bordering neighboring states. The prevalence of persistent opioid use was 10.7% using PDMP data, 5.5% using Surescripts data only, and 11.7% using both data resources.

CONCLUSIONS

The state PDMP appears reliable for detecting opioid fulfillment after surgery, detecting 2 times more patients with persistent opioid use compared with Surescripts.

Localized Pain and Fatigue During Recovery From Submaximal Resistance Exercise in People With Fibromyalgia

OBJECTIVE

Exercise is recommended as a main treatment in fibromyalgia. However, many people have limited exercise tolerance and report exacerbated pain and fatigue during and following a bout of exercise. This study examined the local and systemic changes in perceived pain and fatigue during exercise and through the 3-day recovery following isometric and concentric exercises in people with and without fibromyalgia.

METHODS

Forty-seven participants with a physician diagnosis of fibromyalgia (44 women; mean age [SD] = 51.3 [12.3] years; mean body mass index [SD] = 30.2 [6.9]) and 47 controls (44 women; mean age [SD] = 52.5 [14.7] years; mean body mass index [SD] = 27.7 [5.6]) completed this prospective, observational cohort study. A bout of submaximal resistance exercise (isometric and concentric) was performed localized to the right elbow flexors on 2 separate days. Baseline attributes (pain, fatigue, physical function, physical activity, and body composition) were assessed prior to exercise. Primary outcomes were: change in perceived pain and fatigue (0 to 10 on the visual analog scale) in the exercising limb and whole body during recovery with movement (immediately, 1 day following exercise, and 3 days following exercise). Secondary outcomes were perceived pain and exertion during exercise performance and pain and fatigue at rest during recovery.

RESULTS

Following a single bout of isometric or concentric exercise, there was increased perceived pain (ηp2 = 0.315) and fatigue (ηp2 = 0.426) in the exercising limb, which was greater in people with fibromyalgia (pain: ηp2 = 0.198; fatigue: ηp2 = 0.211). Clinically, relevant increases in pain and fatigue during exercise and through the 3-day recovery occurred in individuals with fibromyalgia only. Concentric contractions led to greater perceived pain, exertion, and fatigue during exercise compared with isometric exercise for both groups.

CONCLUSIONS

People with fibromyalgia experienced significant pain and fatigue in the exercising muscle during recovery from low-intensity and short-duration resistance exercise, with greater pain during concentric contractions.

IMPACT

These findings highlight a critical need to assess and manage pain and fatigue in the exercising muscles of people with fibromyalgia up to 3 days following a single bout of submaximal resistance exercise.

LAY SUMMARY

If you have fibromyalgia, you might have significant pain and fatigue up to 3 days following an exercise bout, with the pain and fatigue localized to the exercising muscles and no changes in whole-body pain.

Targets and study design for symptom-focused trials aimed at patients with cirrhosis: An expert consensus

BACKGROUND

Symptom-focused trials are critically needed for patients with cirrhosis. However, this work would benefit from standard processes and validated measures.

METHODS

A writing group was formed among hepatologists, nurses, palliative care providers, pharmacists, and clinical trial experts focused on symptom management in patients with cirrhosis to define the key (1) components of trial design, (2) symptom targets, (3) measurement, and (4) outcomes for each target. From July 2022 to January 2023, panelists participated in an iterative process of developing and arriving at a consensus for each component. The goal was to provide consensus definitions that can be operationalized in future clinical trials, including for patients with cirrhosis.

RESULTS

The panel reached a consensus on key reporting features for clinical trials, along with considerations for study design. Nine key symptom targets (muscle cramps, pruritus, pain, fatigue, sexual dysfunction, sleep disorders, depression and anxiety, nausea/vomiting, and dyspnea/breathlessness) were identified. The panel selected instruments that can be considered for clinical trials based on psychometric validation and previous experience. The panel identified ongoing needs, including instrument validation, safety data, evidence about non-pharmacologic interventions, and comparative effectiveness studies.

CONCLUSION

This expert panel identified key design, reporting, and measurement elements to standardize processes and measures in future symptom-focused clinical trials in the context of cirrhosis.

Fibromyalgia - etiology, diagnosis and treatment including perioperative management in patients with fibromyalgia

Fibromyalgia (FM) is considered a multifactorial disorder/syndrome with not fully understood etiology. Chronic generalized pain is the main symptom. A broad spectrum of factors is proposed to explain the etiology. Its multifactorial nature is inherently associated with challenges in diagnosis and therapy. Various evidence of etiology has been evaluated with the aim of establishing a novel therapeutic approach. The main issue in the diagnosis and management is to focus on the evaluation of strict diagnostic criteria to minimize under- and overdiagnosis. Fibromyalgia is a challenge for perioperative management because of the increased risk of possible complications and poorer outcomes, including postoperative pain chronification. The authors have proposed an up-to-date evaluation of perioperative management considering the current guidelines. Multimodal analgesia combined with tailored perioperative care is the most appropriate assessment. Interdisciplinary research with special interest in pain management, including perioperative medicine, seems to be the main theme for the future.

Predicting Disease Activity in Rheumatoid Arthritis With the Fibromyalgia Survey Questionnaire: Does the Severity of Fibromyalgia Symptoms Matter?

OBJECTIVE

To determine if the degree of baseline fibromyalgia (FM) symptoms in patients with rheumatoid arthritis (RA), as indicated by the Fibromyalgia Survey Questionnaire (FSQ) score, predicts RA disease activity after initiation or change of a disease-modifying antirheumatic drug (DMARD).

METHODS

One hundred ninety-two participants with active RA were followed for 12 weeks after initiation or change of DMARD therapy. Participants completed the FSQ at the initial visit. The Disease Activity Score in 28 joints using C-reactive protein (DAS28-CRP) was measured at baseline and follow-up to assess RA disease activity. We evaluated the association between baseline FSQ score and follow-up DAS28-CRP. As a secondary analysis, we examined the relationship between the 2 components of the FSQ, the Widespread Pain Index (WPI) and Symptom Severity Scale (SSS), with follow-up DAS28-CRP. Multiple linear regression analyses were performed, adjusting for clinical and demographic variables.

RESULTS

In multiple linear regression models, FSQ score was independently associated with elevated DAS28-CRP scores 12 weeks after DMARD initiation (B = 0.04, P = 0.01). In secondary analyses, the WPI was significantly associated with increased follow-up DAS28-CRP scores (B = 0.08, P = 0.001), whereas the SSS was not (B = -0.03, P = 0.43).

CONCLUSION

Higher levels of FM symptoms weakly predicted worse disease activity after treatment. The primary factor that informed the FSQ's prediction of disease activity was the spatial extent of pain, as measured by the WPI.

Fibromyalgia Increases Post-Operative Healthcare Utilization Following Total Hip Arthroplasty

INTRODUCTION

Pre-operative factors can complicate the post-operative course and increase healthcare utilization following total hip arthroplasty (THA). Fibromyalgia is not generally recognized as a modifiable risk factor prior to THA. The aim of this investigation was to assess the effect of fibromyalgia on post-operative healthcare utilization following THA.

METHODS

Patients who underwent primary THA from 2018 to 2019 were identified from a large national database using Current Procedural Terminology (CPT) and International Classification of Diseases, tenth revision (ICD-10) codes. Patient demographics, age, sex, and pre-operative opioid use were collected. Analysis compared patients who did and did not have fibromyalgia for post-operative healthcare utilization metrics; lengths of stay (LOS), 90-day post-operative opioid usages, dislocations, and emergency room visits. Independent t-testings were used to compare LOS, and rates of ongoing opioid use. Logistic regression analyses with adjusted Odds Ratios (aORs) evaluated the risk of dislocation and emergency room visit after adjusting for demographic characteristics and comorbidities.

RESULTS

Compared to those who did not have fibromyalgia, patients who had fibromyalgia experienced longer LOS (P<0.0001), increased odds of opioid use 90-days post-operatively (P<0.0001), as well as increased odds of hip dislocation (P<0.0001) and presentation to the emergency room (P<0.0001). Patients who had fibromyalgia were also more likely to be "frequent flyers" with >5 emergency room visits after THA (P<0.0001).

CONCLUSIONS

Fibromyalgia can complicate post-operative care following THA with increased LOS, higher rates of opioid use, and increased odds of dislocation and emergency room visits. As focus shifts to pre-operative optimization and risk stratification, more attention should be placed on fibromyalgia prior to THA.

Individualized risk assessment of preoperative opioid use by interpretable neural network regression

Preoperative opioid use has been reported to be associated with higher preoperative opioid demand, worse postoperative outcomes, and increased postoperative healthcare utilization and expenditures. Understanding the risk of preoperative opioid use helps establish patient-centered pain management. In the field of machine learning, deep neural network (DNN) has emerged as a powerful means for risk assessment because of its superb prediction power; however, the blackbox algorithms may make the results less interpretable than statistical models. Bridging the gap between the statistical and machine learning fields, we propose a novel Interpretable Neural Network Regression (INNER), which combines the strengths of statistical and DNN models. We use the proposed INNER to conduct individualized risk assessment of preoperative opioid use. Intensive simulations and an analysis of 34,186 patients expecting surgery in the Analgesic Outcomes Study (AOS) show that the proposed INNER not only can accurately predict the preoperative opioid use using preoperative characteristics as DNN, but also can estimate the patient-specific odds of opioid use without pain and the odds ratio of opioid use for a unit increase in the reported overall body pain, leading to more straight-forward interpretations of the tendency to use opioids than DNN. Our results identify the patient characteristics that are strongly associated with opioid use and is largely consistent with the previous findings, providing evidence that INNER is a useful tool for individualized risk assessment of preoperative opioid use.

Contemporary management of pain in cirrhosis: Toward precision therapy for pain

Chronic pain is highly prevalent in patients with cirrhosis and is associated with poor health-related quality of life and poor functional status. However, there is limited guidance on appropriate pain management in this population, and pharmacologic treatment can be harmful, leading to adverse outcomes, such as gastrointestinal bleeding, renal injury, falls, and hepatic encephalopathy. Chronic pain can be categorized mechanistically into three pain types: nociceptive, neuropathic, and nociplastic, each responsive to different therapies. By discussing the identification, etiology, and treatment of these three mechanistic pain descriptors with a focus on specific challenges in patients with cirrhosis, we provide a framework for better tailoring treatments, including nonpharmacologic therapies, to patients' needs.

Association between nociplastic pain and premature endocrine therapy discontinuation in breast cancer patients

PURPOSE

At least 5 years of adjuvant endocrine therapy (ET) is recommended for patients with hormone receptor-positive invasive breast cancer to reduce cancer recurrence risk. Up to half of patients prematurely discontinue ET, often due to musculoskeletal pain. Nociplastic pain is abnormal central nervous system pain processing without evidence of tissue or neuronal damage. This study aimed to evaluate the relationship between baseline nociplastic pain and ET discontinuation.

METHODS

This was a retrospective, single center, cohort study. Included patients were female, had stage 0-III invasive breast cancer, did not receive neoadjuvant therapy, and completed quality of life questionnaires prior to breast surgery, including Fibromyalgia Survey for nociplastic pain. Clinical data including duration of ET were abstracted from the medical record. Patient characteristics were analyzed with t-tests and Chi-squared tests, as appropriate. Univariate and multivariable regressions were performed with Cox proportional hazard models.

RESULTS

Six hundred eighty-one patients diagnosed between 2012 and 2019 met inclusion criteria; 480 initiated ET and were included in the analysis. Of these 480 patients, 203 (42.3%) prematurely discontinued initial ET therapy. On univariate analysis, tamoxifen use (hazard ratio [HR] 0.70, p = 0.021) and premenopausal status (HR 0.73, p = 0.04) were inversely associated with ET discontinuation, while Fibromyalgia Score was positively associated (HR 1.04, p = 0.043). On multivariable analysis, baseline Fibromyalgia Score remained associated with ET discontinuation.

CONCLUSION

Nociplastic pain present prior to surgery was associated with premature ET discontinuation. Fibromyalgia Score screening may be useful for evaluating ET discontinuation risk. Treatments targeting nociplastic pain may be more effective for treating ET-emergent pain.

Research Trends of Acupuncture Therapy on Fibromyalgia from 2000 to 2021: A Bibliometric Analysis

Purpose

Fibromyalgia Syndrome causes great physical and mental discomfort and incurs high costs. Acupuncture has been regarded as the mainstay of treatment for Fibromyalgia Syndrome while the bibliometric analysis of this field has not been summarized properly. Thus, the purpose of this study is to analyze the hotspot of acupuncture for Fibromyalgia Syndrome.

Methods

The core collection database of Web of Science were searched for relevant publications from 2000 to 2021, and countries, institutions, authors, keywords, and literature were analyzed and visualized by bibliometric software CiteSpace V software and Vosviewer software, to explore the scientific achievements, research collaboration networks, research hot spots, and research trends.

Results

868 publications were included in this study. The publications have increased steadily over time, and the type published the most is Article. Pain is the most cited journal. The most prolific country is the USA while the most prolific institution is Univ Michigan. The most prolific and influential authors were Yiwen Lin and Wolfe F respectively. The analysis of keywords and literature showed that long-term efficacy, animal studies, alternative medicine, and electroacupuncture will be the scientific hotspots in acupuncture for fibromyalgia.

Conclusion

This study shows that the number of research studies, researchers, and research institutions on acupuncture for fibromyalgia is increasing from year to year. Future research hotspots will focus on the long-term efficacy of acupuncture in the treatment of fibromyalgia, experimental animal studies, and the development of other alternative medical therapies. In addition, electroacupuncture is receiving more and more attention as a new application of traditional acupuncture therapy.

Topology of pain networks in patients with temporomandibular disorder and pain-free controls with and without concurrent experimental pain: A pilot study

Temporomandibular disorders (TMD) involve chronic pain in the masticatory muscles and jaw joints, but the mechanisms underlying the pain are heterogenous and vary across individuals. In some cases, structural, functional, and metabolic changes in the brain may underlie the condition. In the present study, we evaluated the functional connectivity between 86 regions of interest (ROIs), which were chosen based on previously reported neuroimaging studies of pain and differences in brain morphology identified in an initial surface-based morphometry analysis. Our main objectives were to investigate the topology of the network formed by these ROIs and how it differs between individuals with TMD and chronic pain (n = 16) and pain-free control participants (n = 12). In addition to a true resting state functional connectivity scan, we also measured functional connectivity during a 6-min application of a noxious cuff stimulus applied to the left leg. Our principal finding is individuals with TMD exhibit more suprathreshold correlations (higher nodal degree) among all ROIs but fewer "hub" nodes (i.e., decreased betweenness centrality) across conditions and across all pain pathways. These results suggest is this pain-related network of nodes may be "over-wired" in individuals with TMD and chronic pain compared to controls, both at rest and during experimental pain.

Autonomic nervous system markers of music-elicited analgesia in people with fibromyalgia: A double-blind randomized pilot study

Purpose

To investigate the feasibility of using music listening by adults with fibromyalgia (FM) as a potential tool for reducing pain sensitivity.

Patients and methods

We report results from a double-blind two-arm parallel randomized pilot study (NCT04059042) in nine participants with FM. Pain tolerance and threshold were measured objectively using quantitative sensory tests; autonomic nervous system (ANS) reactivity was measured with an electrocardiogram. Participants were randomized to listen to instrumental Western Classical music or a nature sound control to test whether music listening elicits greater analgesic effects over simple auditory distraction. Participants also completed separate control testing with no sound that was counterbalanced between participants.

Results

Participants were randomized 1:1 to music or nature sounds (four Music and five Nature). Although the groups were not different on FM scores, the Music group had marginally worse temporal pain summation (p = 0.06), and the Nature group had higher anxiety scores (p < 0.05). Outcome measures showed a significant difference between groups in the magnitude of change in temporal summation between sessions (p < 0.05), revealing that the Nature group had greater pain reduction during audio compared to silence mode, while the Music group had no difference between the sessions. No significant effects were observed for either mechanical pain tolerance or ANS testing. Within the Music group, there was a trend of vagal response increase from baseline to music listening, but it did not reach statistical significance; this pattern was not observed in the Nature group.

Conclusion

Auditory listening significantly altered pain responses. There may be a greater vagal response to music vs. nature sounds; however, results could be due to group differences in pain and anxiety. This line of study will help in determining whether music could be prophylactic for people with FM when acute pain is expected.

The impact of nociplastic pain features on the response to physical therapy in patients with primary myofascial pain

BACKGROUND

Myofascial pain is a common, but poorly understood multifactorial condition.

OBJECTIVE

This study analyzed how the degree of central sensitization (nociplastic pain) can impact the response to physical therapy for patients with myofascial pain.

METHODS

This prospective, observational cohort study compared pain phenotyping and functional measures in 30 participants with non-acute neck/shoulder girdle primary myofascial pain following 3-months of physical therapy. The Fibromyalgia Survey Questionnaire Score served as a surrogate of central sensitization.

RESULTS

All participants demonstrated some benefit from physical therapy; however, those with moderate levels of nociplastic pain features were less likely to have clinically significant improvements on the Neck Disability Index, PEG score, or pain catastrophizing measures. Those with higher levels of nociplastic pain had a similar chance of showing improvement as those with lower levels, except regarding catastrophizing. Significant improvements were independent of the type or amount of therapy received.

CONCLUSION

The degree of nociplastic pain in patients with myofascial pain appears to be inversely related to improvements from a peripherally based treatment. This is not to say that individuals with moderate to higher levels of nociplastic pain do not benefit from physical therapy, but they proportionally benefit less.

Clinical Phenotyping for Pain Mechanisms in Urologic Chronic Pelvic Pain Syndromes: A MAPP Research Network Study

Three categories of pain mechanisms are recognized as contributing to pain perception: nociceptive, neuropathic, and nociplastic (ie, central nervous system augmented pain processing). We use validated questionnaires to identify pain mechanisms in Urologic Chronic Pelvic Pain Syndrome (UCCPS) patients (n = 568, female = 378, male = 190) taking part in the Symptom Patterns Study of the Multidisciplinary Approach to the study of chronic Pelvic Pain Research Network. A cutoff score of 12 on the painDETECT questionnaire (-1 to 38) was used to classify patients into the neuropathic category while the median score of 7 on the fibromyalgia survey criteria (0-31) was used to classify patients into the nociplastic category. Categories were compared on demographic, clinical, psychosocial, psychophysical and medication variables. At baseline, 43% of UCPPS patients were classified as nociceptive-only, 8% as neuropathic only, 27% as nociceptive+nociplastic, and 22% as neuropathic+nociplastic. Across outcomes nociceptive-only patients had the least severe symptoms and neuropathic+nociplastic patients the most severe. Neuropathic pain was associated with genital pain and/or sensitivity on pelvic exam, while nociplastic pain was associated with comorbid pain conditions, psychosocial difficulties, and increased pressure pain sensitivity outside the pelvis. A self-report method classifying individuals on pain mechanisms reveals clinical differences that could inform clinical trials and novel targets for treatment. PERSPECTIVE: This article presents differences in clinical characteristics based on a simple self-report method of classifying pain mechanisms for Urologic Chronic Pelvic Pain Syndrome patients. This method can be easily applied to other chronic pain conditions and may be useful for exploring pathophysiology in pain subtypes.

Correlation of Fibromyalgia Survey Questionnaire and Quantitative Sensory Testing Among Patients With Active Rheumatoid Arthritis

OBJECTIVE

Patients with rheumatoid arthritis (RA) commonly demonstrate disordered pain processing associated with high pain sensitization. Pain sensitization is often assessed using quantitative sensory testing (QST), which is burdensome to patients. The self-administered Fibromyalgia Survey Questionnaire (FSQ) has been proposed as a low-burden, surrogate measure of central pain sensitization. We examined the correlation between FSQ and QST in patients with active RA.

METHODS

Participants in the Central Pain in Rheumatoid Arthritis (CPIRA) cohort underwent FSQ and QST evaluation at enrollment. QST measures included pressure pain threshold (PPT) at the thumb, trapezius, wrist, and knee; temporal summation (TS) at the wrist and arm; and conditioned pain modulation (CPM). Partial Spearman correlation between FSQ and each QST measure was assessed, adjusted for demographic factors, study site, disease characteristics, and pain catastrophizing. Sensitivity analyses included (1) stratified analysis by sex and (2) evaluation of how each component of FSQ associates with the QST measures.

RESULTS

Among 285 participants with active RA, FSQ was weakly but statistically significantly correlated with PPT (r range = -0.31 to -0.21), and TS (r range = 0.13-0.15) at all sites in unadjusted analyses. After adjustment, statistically significant correlations persisted for TS at the wrist and PPT at all sites (except the thumb). Sensitivity analyses did not identify differences in association based on sex or with individual FSQ components.

CONCLUSION

FSQ and QST were correlated among participants with active RA, but the strength of association was weak. QST and FSQ are not interchangeable measures of pain sensitization.

Central sensitization in opioid use disorder: a novel application of the American College of Rheumatology Fibromyalgia Survey Criteria

Central sensitization may be an underlying mechanism linking chronic pain and opioid use disorder associated with opioid use disorder onset, maintenance, escalation, treatment delay, and relapse.

Introduction:

Central sensitization (CS) involves dysfunctional central nervous system pain modulation resulting in heightened pain perception. Central sensitization is not commonly assessed among patients with opioid use disorder (OUD), despite the fact that pain has been implicated in the development, maintenance, and relapse of OUD and chronic opioid use may produce opioid-induced hyperalgesia. Central sensitization is a plausibly important mechanism underlying the complex relationship between OUD and chronic pain. However, this premise is largely untested.

Methods:

Participants with OUD (n = 141) were recruited from an academic addiction treatment center in Columbus, Ohio. An established surrogate measure of CS, the American College of Rheumatology 2011 Fibromyalgia Survey Criteria, was administered using electronic survey. Participants also responded to questions about pain interference (Brief Pain Inventory), quality of life (RAND-36), and items regarding pain beliefs and expectations of pain and addiction treatment. Descriptive analyses, Spearman rho correlations, and Mann–Whitney U tests were performed.

Results:

Hypothesized relationships were confirmed between degree of CS, pain interference, and health-related quality of life. Degree of CS was also positively correlated with greater endorsement of pain as a reason for the onset, maintenance, and escalation of OUD; treatment delay; and OUD relapse. Participants with the American College of Rheumatology 2011 Fibromyalgia Survey Criteria ≥13 had significantly greater endorsement of pain as a reason for delaying OUD treatment, continuing and increasing opioid use, and precipitating OUD relapse.

Conclusions:

This study provides early evidence CS may underlie previously observed connections between clinically salient features of chronic pain and OUD, potentially informing future mechanistic research and precision treatment.

Research Recommendations Following the Discovery of Pain Sensitizing IgG Autoantibodies in Fibromyalgia Syndrome

BACKGROUND

Fibromyalgia syndrome (FMS) is the most common chronic widespread pain condition in rheumatology. Until recently, no clear pathophysiological mechanism for fibromyalgia had been established, resulting in management challenges. Recent research has indicated that serum immunoglobulin Gs (IgGs) may play a role in FMS. We undertook a research prioritisation exercise to identify the most pertinent research approaches that may lead to clinically implementable outputs.

METHODS

Research priority setting was conducted in five phases: situation analysis; design; expert group consultation; interim recommendations; consultation and revision. A dialogue model was used, and an international multi-stakeholder expert group was invited. Clinical, patient, industry, funder, and scientific expertise was represented throughout. Recommendation-consensus was determined via a voluntary closed eSurvey. Reporting guideline for priority setting of health research were employed to support implementation and maximise impact.

RESULTS

Arising from the expert group consultation (n = 29 participants), 39 interim recommendations were defined. A response rate of 81.5% was achieved in the consensus survey. Six recommendations were identified as high priority- and 15 as medium level priority. The recommendations range from aspects of fibromyalgia features that should be considered in future autoantibody research, to specific immunological investigations, suggestions for trial design in FMS, and therapeutic interventions that should be assessed in trials.

CONCLUSIONS

By applying the principles of strategic priority setting we directed research towards that which is implementable, thereby expediating the benefit to the FMS patient population. These recommendations are intended for patients, international professionals and grant-giving bodies concerned with research into causes and management of patients with fibromyalgia syndrome.

Pain Phenotypes in Adults Living With Cerebral Palsy

Background and Objectives

To identify pain phenotypes among adults living with cerebral palsy (CP) and compare phenotypes of pain intensity, anxiety and depressive symptoms, and self-reported perceived stress.

Methods

Seventy-one adults with CP presented to the University of Michigan (mean age = 39.3 ± 16.2; 43 women, 28 men). The median of 6 on the American College of Rheumatology fibromyalgia survey was used to classify patients for nociplastic pain centralization. The painDETECT Score was used to classify patients for neuropathic pain. These measures were then used to cross-classify each patient into 1 of 4 possible pain categories: neuropathic, nociplastic, mixed neuropathic/noclipastic, or nociceptive pain (-neuropathic/-nociplastic pain).

Results

Twenty-eight adults with CP (39.4%) were classified as nociceptive, 24 (33.8%) as nociplastic, 8 (11.3%) as neuropathic, and 11 (15.5%) as mixed neuropathic/nociplastic. Subgroups differed significantly on average scores on the Brief Pain Inventory pain intensity scale, the Perceived Stress Scale, and on the Patient-Reported Outcomes Measurement Information System measures of anxiety and depression; the nociceptive pain subgroup reported lower pain and emotional distress compared with the other groups.

Discussion

Findings suggest that type of pain is variable among adults with CP and may arise through multiple mechanisms.

Mechanism of Chronic Pain of Symptomatic Hip Osteoarthritis by Association of its Distribution, Nociceptive, Neuropathic, Nociplastic, or Mixed-pain Screening, and the Prevalence of Lumbar Spinal Stenosis: A Cross-sectional Study

OBJECTIVES

The pain of hip osteoarthritis (OA) is generally recognized as nociceptive in origin because of the local pathology. However, some patients with OA experience a neuropathic pain component as an essential part of some nociplastic pain subtype. Here, we sought to examine the mechanism of chronic pain of symptomatic hip OA by the association of its distribution, complex pain mechanism screening, and the prevalence of lumbar spinal stenosis.

MATERIALS AND METHODS

We conducted a prospective cross-sectional study of 100 hips in 100 patients with symptomatic hip OA in a chronic state. We examined all baseline clinical characteristics including clinical and functional score, location of pain and numbness, and pain score (PainDETECT questionnaire and the Leeds Assessment of Neuropathic Symptoms and Signs), and magnetic resonance imaging of the hip and lumbar spine.

RESULTS

The PainDETECT questionnaire and Leeds Assessment of Neuropathic Symptoms and Signs revealed that 23% of the patients had a neuropathic pain component. There were 24 variations of the pain pattern. By contrast, the pain localized around the hip joint was only 15%. Pain distal to the thigh and any numbness was significantly more frequent in the group with neuropathic pain (P<0.001). Lumbar spinal stenosis grade was not significantly different between patients with nociceptive pain and those with neuropathic pain. Pain score was significantly correlated with the pain in clinical and functional scores.

DISCUSSION

Among patients with symptomatic hip OA, the distribution of pain was various, and about 23% of patients had neuropathic, nociplastic, or mixed pain as a possibility for somatosensory system disturbances.

Navigating Ethical Challenges for Pediatric Sickle Cell Pain Management in the Context of the Opioid Epidemic

OBJECTIVES

The aim was to describe the impact of the opioid epidemic on pain management practices in pediatric sickle cell disease (SCD) and propose a conceptual framework for navigating ethical decision-making in pediatric sickle cell pain management.

METHODS

A review of the literature on ethical challenges in the management of sickle cell pain was conducted and considered in the context of the opioid epidemic and psychosocial factors affecting youth with SCD. The Integrated Ethical Framework for Pain Management (IEFPM) was applied to pediatric sickle cell pain management using a clinical case example.

RESULTS

Implicit bias, health-related stigma, and potential neurocognitive impairment all present unique challenges in ethical decision-making for youth with SCD. National guidelines for prescribing opioid medication may complicate providers' clinical decision-making and affect their sickle cell pain management practices. The IEFPM was found to be applicable to ethical decision-making for pediatric sickle cell pain and captures both patient-related and provider-related aspects of clinical pain management.

DISCUSSION

The opioid epidemic has exacerbated existing ethical challenges for pain management among youth with SCD. The IEFPM provides a conceptual model that can be integrated into health care settings to facilitate ethical decision-making and promote greater health equity in the clinical management of pediatric sickle cell pain.

The Evolution of Fibromyalgia, Its Concepts, and Criteria

Fibromyalgia developed in the 1950s from a substrate of difficult to explain regional and widespread pain mixed with symptoms of psychosocial distress. Controversies regarding psychological issues were common. Multiple criteria arose to define the disorder, but each identified a different set of patients. The identification of widespread pain as a criterion changed the nature of the disorder by effectively eliminating regional pain as a component condition. The easy-to-measure and relatively reliable widespread pain criterion then came to define the disorder. In the primary care community, diagnostic criteria were largely ignored, and a substantial fraction of diagnosed patients with lower pain scores, particularly women and those with high non-pain symptom scores, were diagnosed. Non-pain symptoms were added back to the fibromyalgia definition and criteria in 2010. Recognition grew that fibromyalgia fit the description of a functional somatic disorder. The idea of fibromyalgia as a primary pain disorder with a neurobiological basis contended with fibromyalgia as a broader biopsychosocial disorder. It is increasingly recognized that fibromyalgia represents a dimensional, non-binary condition and that features of fibromyalgia extend to persons who do not satisfy the criteria. Severity assessments are now available but rarely used. The course of fibromyalgia is not well studied, and improvement and remission criteria have not been successfully defined. The future of fibromyalgia as a discrete disorder remains uncertain as features of fibromyalgia are increasingly observed in patients with multiple different medical conditions.

Recommendations by the Spanish Society of Rheumatology on Fibromyalgia. Part 1: Diagnosis and treatment

OBJECTIVE

To prevent the impairment of fibromyalgia patients due to harmful actions in daily clinical practice that are potentially avoidable.

METHODS

A multidisciplinary team identified the main areas of interest and carried out an analysis of scientific evidence and established recommendations based on the evidence and "formal evaluation" or "reasoned judgment" qualitative analysis techniques.

RESULTS

A total of 39 recommendations address diagnosis, unsafe or ineffective treatment interventions and patient and healthcare workers' education. This part I shows the first 27 recommendations on the first 2 areas.

CONCLUSIONS

Establishing a diagnosis improves the patient's coping with the disease and reduces healthcare costs. NSAIDs, strong opioids and benzodiazepines should be avoided due to side effects. There is no good evidence to justify the association of several drugs. There is also no good evidence to recommend any complementary medicine. Surgeries show a greater number of complications and a lower degree of patient satisfaction and therefore should be avoided if the surgical indication is not clearly established.

Association of Physical Therapy Interventions With Long-term Opioid Use After Total Knee Replacement

IMPORTANCE

Many individuals who undergo total knee replacement (TKR) become long-term opioid users after TKR. Associations of physical therapy (PT) interventions before or after TKR with long-term use of opioids are not known.

OBJECTIVES

To evaluate associations of PT interventions before and after TKR with long-term opioid use after TKR.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from the OptumLabs Data Warehouse on 67 322 individuals aged 40 years or older who underwent TKR from January 1, 2001, to December 31, 2016, stratified by history of opioid use. The analyses for the study included data from January 1, 1999, to December 31, 2018.

EXPOSURES

Any PT interventions within 90 days before or after TKR, post-TKR PT dose as number of sessions (ie, 1-5, 6-12, and ≥13 sessions), post-TKR PT timing as number of days to initiation of care (ie, <30 days, 31-60 days, or 61-90 days after TKR), and post-TKR PT type (ie, active vs passive).

MAIN OUTCOMES AND MEASURES

The association of pre- and post-TKR PT with risk of long-term opioid use occurring more than 90 days after TKR was assessed using logistic regression while adjusting for confounders, including age, sex, race and ethnicity (Asian, Black, Hispanic, or White), obesity, type of insurance, geographical location, and physical and mental health comorbidities.

RESULTS

A total of 38 408 opioid-naive individuals (21 336 women [55.6%]; mean [SD] age, 66.2 [9.2] years) and 28 914 opioid-experienced individuals (18 426 women [63.7%]; mean [SD] age, 64.4 [9.3] years) were included. Receipt of any PT before TKR was associated with lower odds of long-term opioid use in the opioid-naive (adjusted odds ratio [aOR], 0.75 [95% CI, 0.60-0.95]) and opioid-experienced (aOR, 0.75 [95% CI, 0.70-0.80]) cohorts. Receipt of any post-TKR PT was associated with lower odds of long-term use of opioids in the opioid-experienced cohort (aOR, 0.75 [95% CI, 0.70-0.79]). Compared with 1 to 5 sessions of PT after TKR, 6 to 12 sessions (aOR, 0.82 [95% CI, 0.75-0.90]) and 13 or more sessions (aOR, 0.71 [95% CI, 0.65-0.77) were associated with lower odds in the opioid-experienced cohort. Compared with initiation of PT within 30 days after TKR, initiation 31 to 60 days or 61 to 90 days after TKR were associated with greater odds in the opioid-naive (31-60 days: aOR, 1.45 [95% CI, 1.19-1.77]; 61-90 days: aOR, 2.15 [95% CI, 1.43-3.22]) and opioid-experienced (31-60 days: aOR, 1.10 [95% CI, 1.02-1.18]; 61-90 days: aOR, 1.32 [95% CI, 1.12-1.55]) cohorts. Compared with passive PT, active PT was not associated with long-term opioid use in the opioid-naive (aOR, 1.00 [95% CI, 0.81-1.24]) or opioid-experienced (aOR, 0.99 [95% CI, 0.92-1.07]) cohorts.

CONCLUSIONS AND RELEVANCE

This cohort study suggests that receipt of PT intervention before and after TKR, receipt of 6 or more sessions of PT care after TKR, and initiation of PT care within 30 days after TKR were associated with lower odds of long-term opioid use. These findings suggest that PT may help reduce the risk of long-term opioid use after TKR.

Neuro-immune signatures in chronic low back pain subtypes

We recently showed that patients with different chronic pain conditions (such as chronic low back pain, fibromyalgia, migraine, and Gulf War Illness) demonstrated elevated brain and/or spinal cord levels of the glial marker 18 kDa translocator protein, which suggests that neuroinflammation might be a pervasive phenomenon observable across multiple etiologically heterogeneous pain disorders. Interestingly, the spatial distribution of this neuroinflammatory signal appears to exhibit a degree of disease specificity (e.g. with respect to the involvement of the primary somatosensory cortex), suggesting that different pain conditions may exhibit distinct "neuroinflammatory signatures". To further explore this hypothesis, we tested whether neuroinflammatory signal can characterize putative etiological subtypes of chronic low back pain patients based on clinical presentation. Specifically, we explored neuroinflammation in patients whose chronic low back pain either did or did not radiate to the leg (i.e. "radicular" vs. "axial" back pain). Fifty-four chronic low back pain patients, twenty-six with axial back pain (43.7 ± 16.6 y.o. [mean±SD]) and twenty-eight with radicular back pain (48.3 ± 13.2 y.o.), underwent PET/MRI with [11C]PBR28, a second-generation radioligand for the 18 kDa translocator protein. [11C]PBR28 signal was quantified using standardized uptake values ratio (validated against volume of distribution ratio; n = 23). Functional MRI data were collected simultaneously to the [11C]PBR28 data 1) to functionally localize the primary somatosensory cortex back and leg subregions and 2) to perform functional connectivity analyses (in order to investigate possible neurophysiological correlations of the neuroinflammatory signal). PET and functional MRI measures were compared across groups, cross-correlated with one another and with the severity of "fibromyalgianess" (i.e. the degree of pain centralization, or "nociplastic pain"). Furthermore, statistical mediation models were employed to explore possible causal relationships between these three variables. For the primary somatosensory cortex representation of back/leg, [11C]PBR28 PET signal and functional connectivity to the thalamus were: 1) higher in radicular compared to axial back pain patients, 2) positively correlated with each other and 3) positively correlated with fibromyalgianess scores, across groups. Finally, 4) fibromyalgianess mediated the association between [11C]PBR28 PET signal and primary somatosensory cortex-thalamus connectivity across groups. Our findings support the existence of "neuroinflammatory signatures" that are accompanied by neurophysiological changes, and correlate with clinical presentation (in particular, with the degree of nociplastic pain) in chronic pain patients. These signatures may contribute to the subtyping of distinct pain syndromes and also provide information about inter-individual variability in neuro-immune brain signals, within diagnostic groups, that could eventually serve as targets for mechanism-based precision medicine approaches.

Hierarchical clustering by patient-reported pain distribution alone identifies distinct chronic pain subgroups differing by pain intensity, quality, and clinical outcomes

Background

In clinical practice, the bodily distribution of chronic pain is often used in conjunction with other signs and symptoms to support a diagnosis or treatment plan. For example, the diagnosis of fibromyalgia involves tallying the areas of pain that a patient reports using a drawn body map. It remains unclear whether patterns of pain distribution independently inform aspects of the pain experience and influence patient outcomes. The objective of the current study was to evaluate the clinical relevance of patterns of pain distribution using an algorithmic approach agnostic to diagnosis or patient-reported facets of the pain experience.

Methods and findings

A large cohort of patients (N = 21,658) completed pain body maps and a multi-dimensional pain assessment. Using hierarchical clustering of patients by body map selection alone, nine distinct subgroups emerged with different patterns of body region selection. Clinician review of cluster body maps recapitulated some clinically-relevant patterns of pain distribution, such as low back pain with radiation below the knee and widespread pain, as well as some unique patterns. Demographic and medical characteristics, pain intensity, pain impact, and neuropathic pain quality all varied significantly across cluster subgroups. Multivariate modeling demonstrated that cluster membership independently predicted pain intensity and neuropathic pain quality. In a subset of patients who completed 3-month follow-up questionnaires (N = 7,138), cluster membership independently predicted the likelihood of improvement in pain, physical function, and a positive overall impression of change related to multidisciplinary pain care.

Conclusions

This study reports a novel method of grouping patients by pain distribution using an algorithmic approach. Pain distribution subgroup was significantly associated with differences in pain intensity, impact, and clinically relevant outcomes. In the future, algorithmic clustering by pain distribution may be an important facet in chronic pain biosignatures developed for the personalization of pain management.

Multifocal Pain as a Predictor of Pain Outcomes in Military Veterans with Chronic Musculoskeletal Pain: A Secondary Data Analysis of a Randomized Controlled Trial

OBJECTIVE

We aimed to examine 1) the relationship between multifocal pain and clinical characteristics, including demographics, pain outcomes, somatic symptoms, health-related quality of life, depression, and anxiety, and 2) whether multifocal pain was independently associated with treatment response.

METHODS

We conducted a secondary data analysis on veterans with chronic pain enrolled in the Evaluation of Stepped Care for Chronic Pain (ESCAPE) trial with complete data at 9 months (n = 222). We examined baseline relationships and used multivariable linear regression to examine whether multifocal pain was independently associated with outcomes that included Brief Pain Inventory (BPI) Interference scale and Graded Chronic Pain Scale (GCPS) scores between baseline and 9 months.

RESULTS

The sample had a mean BPI Interference score of 5.3 ± 2.2 and a mean GCPS score of 65.6 ± 13.7, 55% had significant depression (Patient Health Questionnaire 9-item depression scale [PHQ-9] score of ≥10), and 42% had significant anxiety (Generalized Anxiety Disorder Scale [GAD-7] score of ≥10). Veterans reporting three or more pain sites (the "more diffuse pain" group) had significantly less improvement on GCPS (b = 4.6, standard error [SE] = 2.3, P = 0.045), BPI Interference (b = 1.0, SE = 0.2, P = 0.0011), and health-related quality of life (Short-Form 36-item scale, Physical Component Summary) (b = 4.1, SE = 1.0, P < 0.0001) than did veterans reporting fewer than three pain sites (the "less diffuse pain" group). More diffuse pain was not associated with changes in PHQ-9 or GAD-7 scores.

CONCLUSIONS

Multifocal pain predicted worse pain outcomes between baseline and 9 months in veterans enrolled in a trial for treating chronic musculoskeletal pain.