Differential sensory and clinical phenotypes of patients with chronic widespread and regional musculoskeletal pain

Widespread pain phenotypes impact treatment efficacy results in randomized clinical trials for interstitial cystitis/bladder pain syndrome: a Multidisciplinary Approach to the Study of Chronic Pelvic Pain network study

ABSTRACT

Pain clinical trials are notoriously complex and often inefficient in demonstrating efficacy, even for known efficacious treatments. A major issue is the difficulty in the a priori identification of specific phenotypes to include in the study population. Recent work has identified the extent of widespread pain as an important determinant of the likelihood of response to therapy, but it has not been tested in clinical trials for the treatment of interstitial cystitis/bladder pain syndrome (IC/BPS). We explored this hypothesis using data from 3 previously published trials testing treatments for IC/BPS, which suggested modest benefits but did not meet a priori primary outcome statistical significance criteria. Importantly, these studies also collected symptom questionnaire data that allowed us to retrospectively identify participants with and without widespread pain. Analyzing the treatment by the degree of widespread pain revealed a difference in outcome and statistical significance level for each trial. Participants with predominately local pain (ie, limited widespread pain symptoms) responded to therapy targeting local symptoms, whereas those with widespread pain did not. Alternatively, participants with widespread pain beyond their local pelvic pain responded to more centrally acting treatments. Our results suggest that differentiating patients based on widespread vs more localized pain is a key consideration for designing future clinical trials for conditions with variable pain profiles, such as IC/BPS and potentially other pain-based syndromic disorders.

Latent class analysis identifies distinct pain phenotypes in newly diagnosed systemic juvenile idiopathic arthritis

BACKGROUND

Patients with systemic juvenile idiopathic arthritis (sJIA) exhibit highly heterogeneous pain manifestations, which significantly impact their quality of life and disease prognosis. An understanding of the pain phenotypes for this disorder and their influencing factors is crucial for individualized pain management.

OBJECTIVE

To explore the pain phenotypes of newly diagnosed sJIA patients via latent class analysis (LCA), analyse the influencing factors of these phenotypes, and evaluate the impacts of different pain phenotypes on short-term inpatient outcomes.

METHODS

A retrospective cohort study was conducted by collecting the electronic health records of 165 patients who were first diagnosed with sJIA at the Children's Hospital of Chongqing Medical University from January 2018 to July 2024. Patient pain characteristics, laboratory indicators, and inpatient outcome data were extracted. LCA was used to identify pain phenotypes, and multivariate logistic regression was used to analyse the influencing factors. The Lanza-Tan-Bray method and the data combination analysis technique were applied to evaluate the relationships between pain phenotypes and clinical outcomes.

RESULTS

LCA categorized the pain phenotypes of sJIA patients into three distinct classes, including (1) Class 1: inflammation-related moderate to severe pain with functional impairment (53.9% of patients); (2) Class 2: mild intermittent pain with extra-articular symptoms (19.4% of patients); and (3) Class 3: no joint pain with mild functional impairment (26.7% of patients). The analysis revealed that age (P = 0.023) and serum IL-10 levels (P = 0.047) were significant factors influencing pain phenotypes. Significant differences were observed among different pain phenotypes in terms of hospital stay duration, intrahospital department transfer rates, and pain status at discharge.

CONCLUSION

Pain in sJIA patients can be classified into three distinct phenotypes, which are influenced by factors such as age and IL-10 levels. The identification of these pain phenotypes has important clinical significance for developing individualized pain management strategies.

From breast cancer diagnosis to survivorship: Analyzing perioperative biopsychosocial phenotypes and their relationship to pain on long term

Persistent breast cancer treatment-related pain affects up to 40% of patients, decreasing their quality of life (QoL). While current research typically utilizes correlation and regression analysis to identify biopsychosocial phenotypes contributing to this pain, this study employs cluster analysis to identify qualitatively different phenotypes based on somatosensory and psychosocial characteristics both before and one week post-breast cancer surgery. Further, it investigates how these phenotypes are related to pain intensity one year post-surgery and examines the evolution of phenotype membership from pre- to post-surgery. Somatosensory and psychosocial functioning was evaluated pre- and post-surgery in 184 women undergoing unilateral breast cancer surgery. Eight different quantitative sensory testing (QST) methods including mechanical detection and pain thresholds, pressure pain thresholds, thermal detection and pain thresholds, and conditioned pain modulation were performed at the surgical area (trunk, arm, major pectoral muscle) and a distant location (quadriceps muscle). Psychosocial functioning was assessed using the Central Sensitization Inventory, Pain Catastrophizing Scale, Depression Anxiety Stress Scale-21, and the McGill Quality of Life Questionnaire. Pain intensity was evaluated one year post-breast cancer surgery using the Visual Analogue Scale. Latent class analysis identified five distinct phenotypes before and post-surgery, characterized by differences in mechanical and pain thresholds alongside psychosocial factors. Moreover, higher psychosocial distress and lower QoL correlated with elevated pain intensity one year post-surgery. These findings underscore the importance of addressing breast cancer patients' mental health perioperatively. Therefore, future research should explore whether psychological interventions perioperatively can reduce long-term pain intensity. PERSPECTIVE: This secondary analysis, utilizing cluster analysis, reveals five distinct phenotype based on somatosensory and psychosocial characteristics both before and post-breast cancer surgery. Higher psychosocial distress and lower quality of life correlated with elevated pain intensity one year post-surgery, emphasizing the need to address patients' mental health perioperatively. TRIAL REGISTRATION: clinicaltrials.gov (NCT03351075).

Night time heart rate predicts next-day pain in fibromyalgia and primary back pain

Introduction

Primary chronic pain is pain that persists for over 3 months without associated measurable tissue damage. One of the most consistent findings in primary chronic pain is its association with autonomic hyperactivation. Yet whether the autonomic hyperactivation causes the pain or results from it is still unclear. It is also unclear to what extent autonomic hyperactivation is related to experienced pain intensity in different subtypes or primary chronic pain.

Objectives

Our first aim was to test lagged relationships between the markers of autonomic activation (heart rate) and pain intensity to determine its directionality. The main question here was whether autonomic biomarkers predict pain intensity or whether pain intensity predicts autonomic biomarkers. The second aim was to test whether this relationship is different between people with primary back pain and people with fibromyalgia.

Methods

Sixty-six patients with chronic pain were observed over an average of 81 days. Sleep heart rate and heart rate variability were measured with a wearable sensor, and pain intensity was assessed from daily subjective reports.

Results

The results showed a predictive relationship between sleep heart rate and next-day pain intensity (P < 0.05), but not between daily pain intensity and next night heart rate. There was no interaction with the type of chronic pain.

Conclusions

These findings suggest that autonomic hyperactivation, whether stress-driven or arising from other causes, precedes increases in primary chronic pain. Moreover, the present results suggest that autonomic hyperactivation is a common mechanism underlying the pain experience in fibromyalgia and chronic back pain.

Do Chronic Low Back Pain and Chronic Widespread Pain differ in their association with Depression Symptoms in the 1958 British Cohort?

OBJECTIVE

Depression frequently coexists with chronic pain. Contemporary models suggest that these conditions share pathobiological mechanisms, prompting a need to investigate their temporal association. This investigation aimed to explore two distinctly different chronic pain conditions, and their cross-sectional and prospective associations with depression.

METHODS

Self-reported information was available on chronic widespread pain (CWP), chronic low back pain (CLBP) (45 years), and depression symptoms (45 and 50 years) from up to 9,377 participants in the 1958 British cohort. Depression symptom outcomes were derived by "Clinical Interview Schedule-Revised" (45 years) and "Short Form-36" (50 years). Relationships between both chronic pain conditions and depression symptoms were investigated by fitting four separate logistic regression models, each with varying levels of covariate adjustment, including depression at baseline.

RESULTS

CWP was associated with depression symptoms cross-sectionally (odds ratio [OR] = 2.04, 95% confidence interval [CI] 1.65, 2.52; P < 0.001, n = 7,629), and prospectively when fully adjusted for baseline, sociodemographic, lifestyle, and health covariates (OR = 1.45, 95% CI 1.17, 1.80; P = < 0.001, n = 6,275). CLBP was associated with depression symptoms prospectively (full model: OR = 1.28, 95% CI 1.01, 1.61; P = 0.04, n = 6,288). In fully adjusted models the prospective association of CWP with depression symptoms was more heavily influenced by our covariates than CLBP with depression symptoms.

CONCLUSION

Pain may be a stressor from which depression can arise. Development of depression may be differentially dependant upon the type of pain experienced. Screening for depression symptoms among individuals with both chronic pain conditions is indicated and should be repeated over time.

Widespread Pain Phenotypes Impact Treatment Efficacy Results in Randomized Clinical Trials for Interstitial Cystitis/Bladder Pain Syndrome: A MAPP Network Study

Clinical trials of pain are notoriously difficult and inefficient in demonstrating efficacy even for known efficacious treatments. Determining the appropriate pain phenotype to study can be problematic. Recent work has identified the extend of widespread pain as an important factor in the likelihood of response to therapy, but has not been tested in clinical trials. Using data from three previously published negative studies of the treatment of interstitial cystitis/ bladder pain with data on the extent of widespread pain, we examined the response of patients to different therapies base on the amount of pain beyond the pelvis. Participants with predominately local but not widespread pain responded to therapy targeting local symptoms. Participants with widespread and local pain responded to therapy targeting widespread pain. Differentiating patients with and without widespread pain phenotypes may be a key feature of designing future pain clinical trials to demonstrate treatments that are effective versus not.

Central Sensitivity and Fibromyalgia

Fibromyalgia presents with symptoms of widespread pain, fatigue, sleeping and cognitive disturbances as well as other somatic symptoms. It often overlaps with other conditions termed 'central sensitivity syndromes' such as irritable bowel syndrome, chronic fatigue syndrome and temporomandibular disorder. Central sensitisation, mediated by amplified processing in the central nervous system, has been identified as the key pathogenic mechanism in these disorders. The term 'central sensitivity' can be used to collectively describe the clinical presentation of these disorders. Fibromyalgia is highly prevalent in most rheumatic diseases as well as non-rheumatic chronic diseases and if unrecognised results in high morbidity. It is diagnosed clinically after excluding important differential diagnoses. Diagnostic criteria have been developed as tools to help identify and diagnose fibromyalgia. Such tools can fulfill an important need when managing patients with rheumatic disease and other chronic diseases as a way to identify fibromyalgia and improve patient outcomes. Treatment involves an integrated approach including education, exercise, stress reduction and pharmacological therapies targeting the central nervous system. This approach is suitable for all presentations of central sensitivity and some central sensitivity syndromes have additional treatment options specific to the clinical presentation. This article is protected by copyright. All rights reserved.