Validation of a questionnaire for Central nervous system Aspects of joint Pain: the CAP questionnaire.

BACKGROUND AND AIMS: Neuropathic-like pain, fatigue, cognitive difficulty, catastrophising, anxiety, sleep disturbance, depression, and widespread pain associate with a single factor in people with knee pain. We report the Central Aspects of Pain questionnaire (CAP) to characterise this across painful musculoskeletal conditions. METHODS: CAP was derived from the 8 item CAP-Knee questionnaire, and completed by participants with joint pain in the Investigating Musculoskeletal Health and Wellbeing survey. Subgroups had osteoarthritis, back pain or fibromyalgia. Acceptability was evaluated by feedback and data missingness. Correlation coefficients informed widespread pain scoring threshold in relation to the other items, and evaluated associations with pain. Factor analysis assessed CAP structure. Intraclass Correlation Coefficient (ICC) between paper and electronic administration assessed reliability. Friedman test assessed score stability over 4 years in people reporting knee osteoarthritis. RESULTS: Data were from 3579 participants (58% female, median age; 71 years), including subgroups with osteoarthritis (n = 1158), back pain (n = 1292) or fibromyalgia (n = 177). Across the 3 subgroups, ≥10/26 painful sites on the manikin scored widespread pain. Reliability was high (ICC= 0.89 (95% CI: 0.84-0.92)) and CAP scores fit to 1 and 2 factor model, with a total CAP score that was associated with pain severity and quality (r = 0.50-0.72). In people with knee pain, CAP scores were stable over 4 years at the group level, but displayed significant temporal heterogeneity within individual participants. CONCLUSIONS: Central Aspects of Pain is reliably measured by the CAP questionnaire across a range of painful musculoskeletal conditions, and is a changeable state.

The bidirectional relationship between chronic joint pain and frailty: data from the Investigating Musculoskeletal Health and Wellbeing cohort.

BACKGROUND: Pain and frailty are associated, but this relationship is insufficiently understood. We aimed to test whether there is a unidirectional or bidirectional relationship between joint pain and frailty. METHODS: Data were from Investigating Musculoskeletal Health and Wellbeing, a UK-based cohort. Average joint pain severity over the previous month was assessed using an 11-point numerical rating scale (NRS). Frailty was classified as present/absent using the FRAIL questionnaire. Multivariable regression assessed the association between joint pain and frailty, adjusted for age, sex, and BMI class. Two-wave cross-lagged path modelling permitted simultaneous exploration of plausible causal pathways between pain intensity and frailty at baseline and 1-year. Transitions were assessed using t-tests. RESULTS: One thousand one hundred seventy-nine participants were studied, 53% female, with a median age of 73 (range 60 to 95) years. FRAIL classified 176 (15%) participants as frail at baseline. Mean (SD) baseline pain score was 5.2 (2.5). Pain NRS ≥ 4 was observed in 172 (99%) of frail participants. Pain severity was associated with frailty at baseline (aOR 1.72 (95%CI 1.56 to 1.92)). In cross-lagged path analysis, higher baseline pain predicted 1-year frailty [ß = 0.25, (95%CI 0.14 to 0.36), p < 0.001] and baseline frailty predicted higher 1-year pain [ß = 0.06, (95%CI 0.003 to 0.11), p = 0.040]. Participants transitioning to frailty over one year had higher mean pain scores (6.4 (95%CI 5.8 to 7.1)) at baseline than those who remained non-frail (4.7 (95%CI 4.5 to 4.8)), p < 0.001. CONCLUSIONS: The bidirectional relationship between pain and frailty could lead to a vicious cycle in which each accelerates the other's progression. This justifies attempts to prevent frailty by addressing pain and to include pain measures as an outcome in frailty studies.

Exploring the disparity between inflammation and disability in the 10-year outcomes of people with rheumatoid arthritis.

OBJECTIVES: To identify groups of people with RA with different disability trajectories over 10 years, despite comparable levels of inflammation. METHODS: Data for this analysis came from three European prospective cohort studies of people with RA [Norfolk Arthritis Register (NOAR), Early RA Network (ERAN), Étude et Suivi des Polyarthrites Indifférenciées Récentes (ESPOIR)]. Participants were assessed regularly over 8 (ERAN) to 10 (NOAR/ESPOIR) years. Inclusion criteria were: recruited after 1 January 2000, <24 months baseline symptom duration, and disability (HAQ) and inflammation [two-component DAS28 (DAS28-2C)] recorded at baseline and at one other follow-up. People in each cohort also completed patient-reported outcome measures at each assessment (pain, fatigue, depressive symptoms). Group-based trajectory models were used to identify distinct groups of people with similar HAQ and DAS28-2C trajectories over follow-up. RESULTS: This analysis included 2500 people with RA (NOAR: 1000, ESPOIR: 766, ERAN: 734). ESPOIR included more women and the participants were younger [mean (standard deviation) age: NOAR: 57.1 (14.6), ESPOIR: 47.6 (12.5), ERAN: 56.8 (13.8); women: NOAR: 63.9%, ESPOIR: 76.9%, ERAN: 69.1%). Within each cohort, two pairs of trajectories following the hypothesized pattern (comparable DAS28-2Cs but different HAQs) were identified. Higher pain, fatigue and depressive symptoms were associated with increased odds of being in the high HAQ trajectories. CONCLUSION: Excess disability is persistent in RA. Controlling inflammation may not be sufficient to alleviate disability in all people with RA, and effective pain, fatigue and mood management may be needed in some groups to improve long-term function.

The efficacy of systemic glucocorticosteroids for pain in rheumatoid arthritis: a systematic literature review and meta-analysis.

OBJECTIVES: Glucocorticosteroids (GCs) are recommended to suppress inflammation in people with active RA. This systematic review and meta-analysis aimed to quantify the effects of systemic GCs on RA pain. METHODS: A systematic literature review of randomized controlled trials (RCTs) in RA comparing systemic GCs to inactive treatment. Three databases were and spontaneous pain and evoked pain outcomes were extracted. Standardized mean differences (SMDs) and mean differences were meta-analysed. Heterogeneity (I2, tau statistics) and bias (funnel plot, Egger's test) were assessed. Subgroup analyses investigated sources of variation. This study was pre-registered (PROSPERO CRD42019111562). RESULTS: A total of 18 903 titles, 880 abstracts and 226 full texts were assessed. Thirty-three RCTs suitable for the meta-analysis included 3123 participants. Pain scores (spontaneous pain) decreased in participants treated with oral GCs; SMD = -0.65 (15 studies, 95% CI -0.82, -0.49, P <0.001) with significant heterogeneity (I2 = 56%, P =0.0002). Efficacy displayed time-related decreases after GC initiation. Mean difference visual analogue scale pain was -15 mm (95% CI -20, -9) greater improvement in GC than control at ≤3 months, -8 mm (95% CI -12, -3) at >3-6 months and -7 mm (95% CI -13, 0) at >6 months. Similar findings were obtained when evoked pain outcomes were examined. Data from five RCTs suggested improvement also in fatigue during GC treatment. CONCLUSION: Oral GCs are analgesic in RA. The benefit is greatest shortly after initiation and GCs might not achieve clinically important pain relief beyond 3 months. Treatments other than anti-inflammatory GCs should be considered to reduce the long-term burden of pain in RA.

Investigating musculoskeletal health and wellbeing; a cohort study protocol.

BACKGROUND: In an ageing population, pain, frailty and disability frequently coexist across a wide range of musculoskeletal diagnoses, but their associations remain incompletely understood. The Investigating Musculoskeletal Health and Wellbeing (IMH&W) study aims to measure and characterise the development and progression of pain, frailty and disability, and to identify discrete subgroups and their associations. The survey will form a longitudinal context for nested research, permitting targeted recruitment of participants for qualitative, observational and interventional studies; helping to understand recruitment bias in clinical studies; and providing a source cohort for cohort randomised controlled trials. METHODS: IMH&W will comprise a prospective cohort of 10,000 adults recruited through primary and secondary care, and through non-clinical settings. Data collection will be at baseline, and then through annual follow-ups for 4 years. Questionnaires will address demographic characteristics, pain severity (0-10 Numerical Rating Scale), pain distribution (reported on a body Manikin), pain quality (McGill Pain Questionnaire), central aspects of pain (CAP-Knee), frailty and disability (based on Fried criteria and the FRAIL questionnaire), and fracture risk. Baseline characteristics, progression and associations of frailty, pain and disability will be determined. Discrete subgroups and trajectories will be sought by latent class analysis. Recruitment bias will be explored by comparing participants in nested studies with the eligible IMH&W population. DISCUSSION: IMH&W will elucidate associations and progression of pain, frailty and disability. It will enable identification of people at risk of poor musculoskeletal health and wellbeing outcomes who might be suitable for specific interventions, and facilitate generalisation and comparison of research outcomes between target populations. The study will benefit from a large sample size and will recruit from diverse regions across the UK. Purposive recruitment will enrich the cohort with people with MSK problems with high representation of elderly and unwell people. TRIAL REGISTRATION: Clinicaltrials.gov NCT03696134. Date of Registration: 04 October 2018.

CGRP and Painful Pathologies Other than Headache.

CGRP has long been suspected as a mediator of arthritis pain, although evidence that CGRP directly mediates human musculoskeletal pain remains circumstantial. This chapter describes in depth the evidence surrounding CGRP's association with pain in musculoskeletal disorders and also summarises evidence for CGRP being a direct cause of pain in other conditions. CGRP-immunoreactive nerves are present in musculoskeletal tissues, and CGRP expression is altered in musculoskeletal pain. CGRP modulates musculoskeletal pain through actions both in the periphery and central nervous system. Human observational studies, research on animal arthritis models and the few reported randomised controlled trials in humans of treatments that target CGRP provide the context of CGRP as a possible pain biomarker or mediator in conditions other than migraine.

Pain mechanisms in rheumatoid arthritis.

Understanding of the causes and underlying mechanisms of pain in people with RA is rapidly changing. With the advent of more effective disease modifying drugs, joint inflammation is becoming a more treatable cause of pain, and joint damage can often be prevented. However, the long-term prognosis for pain still is often unfavourable, even after inflammation is suppressed. Pain is associated with fatigue and psychological distress, and RA pain qualities often share characteristics with neuropathic pain. Each of these characteristics suggests key roles for central neuronal processing in RA pain. Pain processing by the central nervous system can maintain and augment RA pain, and is a promising target for future treatments. Inflammatory mediators, such as cytokines, may provoke central pain sensitisation in animal models, and both local and systemic inflammation might contribute to central pain augmentation in RA. Controlled trials of treatments that target central pain processing have shown some benefit in people with RA, and might be most effective in individuals for whom central pain augmentation plays a key role. For people with RA who experience persistent pain, identifying underlying pain mechanisms critically determines the balance between escalation of anti-inflammatory and disease-modifying treatments and other strategies to provide symptomatic analgesia.

Erosive and osteoarthritic structural progression in early rheumatoid arthritis.

OBJECTIVES: To investigate factors associated with joint damage in early RA, and how comorbid OA might influence patient assessment and outcomes. METHODS: Baseline radiographs of hands and feet from 512 participants in the Early RA Network cohort, and after 3 (±1) years, 166 of those participants yielded complete scores for RA [erosions, joint space narrowing (JSN)] and OA [JSN, osteophytes (OST)] using validated atlases. DAS28-P is the proportion of DAS28 attributed to patient-reported factors. Adjusted odds ratios were calculated using logistic regression. RESULTS: OA was common at baseline in early RA (40% hand and 48% foot) and associated with RA radiographic score. Higher baseline RA scores were associated with increasing age and ESR, and lower DAS28-P. OST scores were associated with higher age. DAS28 and patient-reported outcomes improved, whereas RA and OA radiographic scores deteriorated by follow-up. Erosive progression was predicted by higher baseline erosions, female gender, better mental health and lower DAS28-P. Hand OST progression was predicted by baseline OST scores. Inflammatory disease activity was associated with erosive, but not with OA progression. Baseline hand OA predicted worse physical function at follow-up, but radiographic progression did not explain changes in patient-reported outcomes. CONCLUSION: OA is a common comorbidity that might confound radiographic and clinical assessment, but does not fully explain erosive progression or patient-reported outcomes in early RA. Early RA management should address psychosocial factors and comorbidities, as well as joint inflammation.

Factors predicting pain and early discontinuation of tumour necrosis factor-α-inhibitors in people with rheumatoid arthritis: results from the British society for rheumatology biologics register.

BACKGROUND: We examined pain levels in 2 cohorts assembled from the British Society for Rheumatology Biologics Register (BSRBR), and investigated which factors predicted Bodily Pain scores and discontinuation of TNFα-inhibitors. METHOD: Data were retrieved from BSRBR-RA databases for up to 1 year after commencing TNFα-inhibitors (n = 11995) or being treated with non-biologic therapies (n = 3632). Bodily Pain scores were derived from the Short Form-36 (SF36) questionnaire and norm-transformed to allow comparison with UK population averages. Discontinuation data were from physician reports. Other data, including 28-joint disease activity score (DAS28) measurements, were from clinical examination, interview, medical records and self-report questionnaires. DAS28-P was derived as the proportion of DAS28 attributed to patient-reported factors (tender joint count and visual analogue score). Missing baseline variables from both cohorts were imputed into 20 replicate datasets. Odds ratios (OR) and adjusted OR were calculated for higher than median pain within each cohort. RESULTS: Participants reported moderate to severe pain at baseline, and pain scores remained >1SD worse than normal population standards at 1 year, even when disease activity responded to treatment. Baseline pain was associated with DAS28-P, worse physical function, worse mental health, and DAS28. After logistic regression, independent predictors of higher than median pain at follow up were baseline Bodily Pain score, higher DAS28-P, worse physical function or mental health and co-morbidities. Higher age, male gender, and higher BMI were additional independent predictors of higher pain in participants who received TNFα-inhibitors. Baseline pain was also one of the predictors of discontinuation of the first TNFα-inhibitor within 1 year, as were female gender, current smoking, co-morbidities, extra-articular manifestations and worse function. CONCLUSION: Pain persists in people with treated RA, even in those for whom inflammation responds to treatment. Worse pain outcomes are predicted by factors different to those typically found to predict inflammatory disease activity in other studies. Worse pain at baseline also predicts discontinuation of TNFα-inhibitors. Improved pain management should complement inflammatory disease suppression in RA.

Work disability and state benefit claims in early rheumatoid arthritis: the ERAN cohort.

OBJECTIVE: RA is an important cause of work disability. This study aimed to identify predictive factors for work disability and state benefit claims in a cohort with early RA. METHODS: The Early RA Network (ERAN) inception cohort recruited from 22 centres. At baseline, and during each annual visit, participants (n = 1235) reported employment status and benefits claims and how both were influenced by RA. Survival analysis derived adjusted hazard ratios (aHRs) and 95% CIs to predict associations between baseline factors and time until loss of employment due to RA or a state benefits claim due to RA. RESULTS: At baseline, 47% of participants were employed and 17% reported claiming benefits due to RA. During follow-up, loss of employment due to RA was reported by 10% (49/475) of the participants and 20% (179/905) began to claim benefits. Independent predictors of earlier work disability were bodily pain (aHR 2.45, 95% CI 1.47, 4.08, P = 0.001) and low vitality (aHR 1.84, 95% CI 1.18, 2.85, P = 0.007). Disability (aHR 1.28, 95% CI 1.02, 1.61, P = 0.033), DAS28 (aHR 1.48, 95% CI 1.05, 2.09, P = 0.026) and extra-articular disease (aHR 1.77, 95% CI 1.17, 2.70, P = 0.007) predicted earlier benefits claims. CONCLUSION: Work disability and benefits claims due to RA were predicted by different baseline factors. Pain and low vitality predicted work disability. Baseline disability, extra-articular disease manifestations and disease activity predicted new benefits claims due to RA. Future research on interventions targeting these factors could investigate job retention and financial independence.

Self-reported adult footwear and the risks of lower limb osteoarthritis: the GOAL case control study.

BACKGROUND: Biomechanical factors may play a role in osteoarthritis (OA) development and progression. Previous biomechanical studies have indicated that types of footwear may modulate forces across the knee joint, and high heeled womens' shoes in particular are hypothesised to be detrimental to lower limb joint health. This analysis of data from a case control study investigated persistent users of different adult footwear for risks of knee and hip OA. Our underlying hypotheses were that high heeled, narrow heeled, and hard soled shoe types were putative risk factors for lower limb OA. METHODS: Data on footwear were initially obtained from participants during the Genetics of Osteoarthritis and Lifestyle (GOAL) hospital-based, case control study using standardised interview-delivered questionnaires. An additional questionnaire was later sent to GOAL study participants to verify findings and to further investigate specific shoe use per decade of life. Persistent users of footwear types (high or narrow heel; sole thickness or hardness) were identified from early adulthood. Participants were grouped into single sex knee OA, hip OA or control groups. Adjusted odds ratios (aOR) and 95% confidence interval (CI) were calculated. RESULTS: Univariate analysis of persistent users of women's high heeled and narrow heeled shoes during early adulthood showed negative associations with knee OA and hip OA. After logistic regression, persistent narrow heel users were associated with less risk of OA (knee OA aOR 0.59, 95% CI 0.35 - 1.00 and hip aOR: 0.50, 95% CI 0.30 - 0.85), and other analyses were not statistically significant. Further analysis suggested that women with hip OA may have stopped wearing high and narrow heeled footwear to attenuate hip pain in early adulthood. Consistent associations between shoe soles and OA were not found. CONCLUSIONS: In general, persistent users of high and narrow heeled shoes during early adulthood had a negative association with knee or hip OA. This does not necessarily imply a causal relationship, as changing footwear during early adulthood to modulate index joint pain may provide a possible explanation. Despite the findings of previous biomechanical studies of high heels, we did not find a positive association between women's shoes and lower limb osteoarthritis.

Influence of central aspects of pain on self-management in people with chronic low back pain.

OBJECTIVE: This observational study investigated whether central aspects of pain are associated with self-management domains in individuals with chronic low back pain (CLBP) undertaking a pain management program. METHODS: Individuals with CLBP provided pain sensitivity and self-management data at baseline (n = 97) and 3-months (n = 87). Pressure pain detection threshold (PPT) at the forearm, temporal summation (TS) and conditioned pain modulation (CPM), Widespread Pain Index (WPI), and a Central Aspects of Pain factor (CAPf) were considered as central aspects of pain. Self-management was measured using the 8 domains of the Health Education Impact Questionnaire, as well as Pain Self Efficacy and Health Care Utilisation questionnaires. RESULTS: PPT, CPM, WPI and CAPf predicted worse performance in several self-management domains at 3-months (r = 0.21 to 0.54, p < 0.05 overall). In multivariable regression models (adjusted for baseline scores of self-management, depression, catastrophization, pain and fatigue) low PPT, high TS, and high CAPf at baseline predicted poorer self-management at 3 months (R2 =0.14 to 0.52, ß = -0.37 to 0.35, p < 0.05). CONCLUSIONS: Central aspects of pain are associated with impaired self-management, over and above effects of pain intensity, fatigue, depression and catastrophizing. PRACTICE IMPLICATIONS: Treatments that target central aspects of pain might help improve self-management in people with CLBP.

Contribution of inflammation markers and quantitative sensory testing (QST) indices of central sensitisation to rheumatoid arthritis pain.

BACKGROUND: Pain, the primary complaint in rheumatoid arthritis (RA), is multifaceted, and may be driven by inflammatory disease activity and central sensitisation. We aimed to ascertain what proportion of RA pain severity is explained by markers of inflammation and quantitative sensory testing (QST) indices of central sensitisation. METHODS: This was a cross-sectional analysis of data from individuals with clinically active RA. Pain severity was assessed using numerical rating scales and inflammation via 28-joint Disease Activity Score (DAS28) and Ultrasound (Greyscale, Power Doppler). Pain sensitivity was assessed by 'static' (tibialis anterior or brachioradialis pressure pain detection threshold-PPT-TA/PPT-BR) and 'dynamic' (temporal summation-TS, conditioned pain modulation-CPM) QST. Bivariate associations used Spearman's correlation coefficients, and multivariable linear regression models determined relative contributions to pain severity. RESULTS: In bivariate analyses of N = 96 (age 65 ± 10y, 77% females) people with RA, pain severity was significantly associated with inflammation indices (r = 0.20 to 0.55), and CPM (r=-0.26). In multivariable models that included TS, CPM, age, sex, and body mass index, inflammation indices remained significantly associated with pain severity. Multivariable models explained 22 to 27% of pain variance. Heterogeneity was apparent for associations with pain between subscores for pain now, strongest or average over the past 4-weeks. CONCLUSIONS: In individuals with clinically active RA, markers of inflammatory disease activity best explain RA pain with only marginal contributions from QST indices of central sensitisation. Although inflammation plays a key role in the experience of RA pain, the greater proportion of pain severity remains unexplained by DAS28 and ultrasound indices of inflammation.

Baseline factors predicting change from the initial DMARD treatment during the first 2 years of rheumatoid arthritis: experience in the ERAN inception cohort.

BACKGROUND: Outcomes in early Rheumatoid Arthritis (RA) may be improved by rapidly establishing a stable and effective disease modifying anti-rheumatic drug (DMARD) treatment regimen. We aimed to investigate whether baseline factors and initial treatment strategies are associated with changes to the first DMARD treatment, due to either Lack of Efficacy (LoE) or Adverse Drug Reaction (ADR) within 2 years of presentation. METHODS: Reasons for changes from initial DMARD therapy within 2 years of baseline, and associated factors, were examined using logistic regression in data from the Early RA Network (ERAN) inception cohort. RESULTS: Data were available for 766 participants. 410 (54%) changed their initial DMARD regime within 2 years, including 230 (56%) due to Lack of Efficacy (LoE) and 139 (34%) due to Adverse Drug Reaction (ADR). The first DMARD was recorded as methotrexate monotherapy in 336 (44%), sulphasalazine monotherapy in 273 (36%), or combined methotrexate/sulphasalazine/hydroxychlorquine in 52 (7%).Baseline predictors of changing DMARD (for all reasons) were HAQ-disability (aOR 1.44, 95% CI 1.12 - 1.86), poor mental health (aOR 1.44, 95% CI 1.16 - 1.78) and extra-articular disease (aOR 1.78, 95% CI 1.00 - 3.16). In this model, the triple combination therapy also predicted lower likelihood of DMARD change (aOR 0.30, 95% CI 0.12 - 0.79).Subgroup analyses showed that MTX monotherapy was associated with lower risk of change due to ADR. Combination therapy conferred lower risk of change due to LoE. Poor mental health was associated with change due to ADR, and extra-articular disease, HAQ-disability at baseline, and younger age predicted LoE. CONCLUSIONS: Our findings suggest that non-pharmacological interventions to improve disability and mental health, may reduce initial DMARD treatment failure.

The interrater and test-retest reliability of 3 modalities of quantitative sensory testing in healthy adults and people with chronic low back pain or rheumatoid arthritis.

Introduction: Quantitative Sensory Testing (QST) modalities used to assess central pain mechanisms require different protocols in people with different musculoskeletal conditions. Objectives: We aimed to explore the possible effects of musculoskeletal diagnosis and test site on QST interrater and test-retest reliability. Methods: The study included participants with rheumatoid arthritis (RA, n = 18; QST conducted on lower leg) and low back pain (LBP, n = 25; QST conducted on forearm), plus 45 healthy control participants (n = 20 QST on lower leg and n = 25 QST on forearm). Test-retest reliability was assessed from QST conducted 1 to 3 weeks apart. Quantitative sensory testing modalities used were pressure pain detection threshold (PPT) at a site distant to tissue pathology, temporal summation (TS), and conditioned pain modulation (CPM). Temporal summation was calculated as difference or ratio of single and repeated punctate stimuli and unconditioned thresholds for CPM used single or mean of multiple PPTs. Intraclass correlation coefficients (ICCs) were compared between different subgroups. Results: High to very high reliability was found for all assessments of PPT and TS across anatomical sites (lower leg and forearm) and participants (healthy, RA, and LBP) (ICC ≥ 0.77 for PPT and ICC ≥ 0.76 for TS). Reliability was higher when TS was calculated as a difference rather than a ratio. Conditioned pain modulation showed no to moderate reliability (ICC = 0.01-0.64) that was similar between leg or forearm, and between healthy people and those with RA or LBP. Conclusion: PPT and TS are transferable tools to quantify pain sensitivity at different testing sites in different musculoskeletal diagnoses. Low apparent reliability of CPM protocols might indicate minute-to-minute dynamic pain modulation.

How people with knee pain understand why their pain changes or remains the same over time: A qualitative study.

Objectives: Guidelines recommend knee osteoarthritis pain management based on biopsychosocial mechanisms. Treatment adherence and effectiveness may be affected if there is a mismatch between patient perspectives and treatment focus. We therefore examined patient perspectives on mechanisms of their knee pain, why it persisted or changed over the past year, whether their understanding had changed, and whether their understanding aligned with that of others with whom they interact. Methods: Individuals with chronic knee pain (n â€‹= â€‹50) were purposively recruited from the Knee Pain and related health In the Community (KPIC) cohort to represent worsened, improved, or unchanged pain or anxiety between baseline and one year later. Framework analysis, a comparative form of thematic analysis, was used across transcripts of semi-structured telephone interviews. Results: Data were collapsed into themes of diagnosis, joint structure, ageing, physical activity, weight management, and treatment. Participants focused on biomechanical rather than psychological pain mechanisms. Some participants attributed pain improvement to increased and others to decreased physical activity. Participants reported no change in their understanding of their pain during the preceding year, but that their attitudes to pain, for example acceptance, had changed. Participants reported that they and others around them lacked understanding of their pain and why it did or did not change. Conclusion: People report a predominantly biomechanical understanding of why their knee pain remains constant or changes over time. Clinicians should support patients to develop a biopsychosocial understanding of knee pain aligned to treatment across the range of biological, psychological, and social modalities.

Associations of Muscle Strength with Central Aspects of Pain: Data from the Knee Pain and Related Health in the Community (KPIC) Cohort.

Knee pain is associated with lower muscle strength, and both contribute to disability. Peripheral and central neurological mechanisms contribute to OA pain. Understanding the relative contributions of pain mechanisms to muscle strength might help future treatments. The Knee Pain and related health In the Community (KPIC) cohort provided baseline and year 1 data from people with early knee pain (n = 219) for longitudinal analyses. A cross-sectional analysis was performed with baseline data from people with established knee pain (n = 103) and comparative data from people without knee pain (n = 98). Quadriceps and handgrip strength indicated local and general muscle weakness, respectively. The indices of peripheral nociceptive drive were knee radiographic and ultrasound scores. The indices associated with central pain mechanisms were Pressure Pain detection Threshold (PPT) distal to the knee, and a validated self-report Central Aspects of Pain Factor (CAPF). The associations were explored using correlation and multivariable regression. Weaker quadriceps strength was associated with both high CAPF and low PPT at baseline. Year 1 quadriceps weakness was predicted by higher baseline CAPF (ß = -0.28 (95% CI: -0.55, -0.01), p = 0.040). Weaker baseline and year 1 handgrip strength was also associated with higher baseline CAPF. Weaker baseline quadriceps strength was associated with radiographic scores in bivariate but not adjusted analyses. Quadriceps strength was not significantly associated with total ultrasound scores. Central pain mechanisms might contribute to muscle weakness, both locally and remote from the knee.

Influence of Social Support, Financial Status, and Lifestyle on the Disparity Between Inflammation and Disability in Rheumatoid Arthritis.

OBJECTIVE: To investigate how social support, financial status, and lifestyle influence the development of excess disability in rheumatoid arthritis (RA). METHODS: Data were obtained from the Étude et Suivi des Polyarthrites Indifférenciées Récentes (ESPOIR) cohort study of people with RA. A previous analysis identified groups with similar inflammation trajectories but markedly different disability over 10 years; those in the higher disability trajectory groups were defined as having "excess disability." Self-reported data regarding contextual factors (social support, financial situation, lifestyle) were obtained from participants, and they completed patient-reported outcome measures (pain, fatigue, anxiety, depression) at baseline. The direct effect of the contextual factors on excess disability and the effect mediated by patient-reported outcome measures were assessed using structural equation models. Findings were validated in 2 independent data sets (Norfolk Arthritis Register [NOAR], Early Rheumatoid Arthritis Network [ERAN]). RESULTS: Of 538 included ESPOIR participants (mean age ± SD 48.3 ± 12.2 years; 79.2% women), 200 participants (37.2%) were in the excess disability group. Less social support (ß = 0.17 [95% confidence interval (95% CI) 0.08, 0.26]), worse financial situation (ß = 0.24 [95% CI 0.14, 0.34]), less exercise (ß = 0.17 [95% CI 0.09-0.25]), and less education (ß = 0.15 [95% CI 0.06, 0.23]) were associated with excess disability group membership; smoking, alcohol consumption, and body mass index were not. Fatigue and depression mediated a small proportion of these effects. Similar results were seen in NOAR and ERAN. CONCLUSION: Greater emphasis is needed on the economic and social contexts of individuals with RA at presentation; these factors might influence disability over the following decade.

Pain in rheumatoid arthritis.

Rheumatoid arthritis (RA) is an inflammatory disease of synovial joints, and pain is the predominant problem for people with RA. Pain in RA is distressing in its own right and adversely affects disability and psychosocial outcomes. RA pain may be due to joint inflammation and also augmented by central sensitization and structural joint damage. Noninflammatory pain mechanisms may confound the assessment of disease activity in RA, and treatment should aim to both suppress inflammatory disease and relieve pain symptoms. Effective treatment stratification requires a full assessment of pain mechanisms by clinical history and examination, as well as objective assessment of synovitis and joint damage. Biologic therapies and joint replacement surgery have major impacts on RA pain, but may only be available to those with most severe or advanced disease. Holistic approaches to pain management are indicated, including pharmacologic analgesia where randomized controlled trials (RCTs) offer evidence of efficacy.