The journal of pain : official journal of the American Pain Society
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Exploring the relationship between underlying pain mechanisms and physical activity could inform interventions to optimize physical activity in persons with multiple sclerosis (PwMS). This cross-sectional nationwide survey examined whether pain phenotype is a significant predictor of self-reported physical activity in PwMS. The study included 938 persons with a self-reported diagnosis of MS (93% reported neurologist-diagnosed MS) who completed surveys of demographic, clinical information, pain intensity, indicators of underlying pain mechanisms (Fibromyalgia Survey Criteria and painDETECT), and physical activity (Godin Leisure-Time Exercise Questionnaire). ⋯ This suggests that assessing pain phenotype may be important to identify individuals at risk of inadequate physical activity and may guide the tailoring of behavioral therapeutic approaches to help PwMS achieve the recommended level of physical activity. PERSPECTIVE: This study examines the association between pain mechanism and physical activity in multiple sclerosis. These findings highlight the possibility that a basic screening for pain mechanism could offer clinically useful information without requiring extensive neurobiological phenotyping and may inform the development of behavioral interventions to enhance physical activity in multiple sclerosis.
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Inflammation is linked with chronic pain but the extent to which this relationship is associated with biopsychosocial factors is not known. We investigated relationships between blood C-reactive protein (CRP) and regional chronic pain conditions adjusting for a large range and number of potential confounders. We performed cross-sectional analyses using the UK Biobank (N = 415,567) comparing CRP in people reporting any of 9 types of regional chronic pain with pain-free controls. ⋯ Our findings may inform better-targeted treatments for chronic pain. PERSPECTIVE: Using a large-scale dataset, this article investigates associations between chronic pain conditions and blood C-reactive protein (CRP), to evaluate the confounding effects of a range of biopsychosocial factors. CRP levels were higher in those with chronic pain versus controls after adjusting for confounders-suggesting a possible independent biological mechanism.
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Meta Analysis
Characterisation of common genetic variants in P2RX7 and their contribution to chronic pain conditions.
The adenosine triphosphate (ATP)-gated channel P2X7 is encoded by a gene enriched for common nonsynonymous variants. Many of these variants have functional cellular effects, and some have been implicated in chronic pain. In this study, we first systematically characterized all 17 common nonsynonymous variants using whole-cell patch clamp electrophysiology. ⋯ Cumulative allele count analysis did not provide additional insights. In conclusion, our results go beyond reproducing association for rs7958311 with chronic pain and suggest that its unique combination of gain-of-function in channel and loss-of-function in pore activity may explain why it is likely the only common P2RX7 variant with contribution to chronic pain. PERSPECTIVE: This study characterizes all common P2RX7 variants using cellular assays and statistical association analyses with chronic pain, with Markov state modeling of the most robustly associated variant.
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This prospective cohort study investigates the prognosis of patients with neuropathic low back-related leg pain consulting in UK primary care. Data from 511 patients were collected using standardised baseline clinical examinations (including magnetic resonance imaging scan findings), self-report questionnaires at baseline, 4 months, 12 months, and 3 years. Cases of possible neuropathic pain (NP) and persistent-NP were identified using either of 2 definitions: 1) clinical diagnosis of sciatica, 2) self-report version of leeds assessment for neurological symptoms and signs (s-LANSS). ⋯ PERSPECTIVE: This study provides evidence that neuropathic back-related leg pain in patients consulting in primary care is not always persistent. Patients with persistent neuropathic pain had worse outcomes than those without. Neither leg pain intensity, pain self-efficacy nor MRI scan findings predicted cases of persistent neuropathic pain in this patient population.
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Review Meta Analysis
Conditioned pain modulation and temporal summation of pain in patients with traumatic and non-specific neck pain: a systematic review and meta-analysis.
In patients with neck pain, it is unclear whether pain inhibition and facilitation endogenous pain mechanisms are altered. This systematic review and meta-analysis aimed to improve their understanding by assessing conditioned pain modulation (CPM) and temporal summation of pain (TSP) in patients with neck pain associated with whiplash-associated disorders (WAD) or of a nonspecific neck pain (NSNP) nature compared to pain-free controls. Very low certainty evidence suggests: impaired CPM when assessed remotely in chronic WAD patients (n = 7, 230 patients and 204 controls, standardized mean differences (SMD) = -.47 [-.89 to -.04]; P = .04) but not locally (n = 6, 155 patients and 150 controls; SMD = -.34 [-.68 to .01]; P = .05), impaired CPM in chronic NSNP patients when assessed locally (n = 5, 223 patients and 162 controls; SMD = -.55 [-1.04 to -.06]; P = .04) but not remotely (n = 3, 72 patients and 66 controls; SMD = -.33 [-.92 to .25]; P = .13), TSP not facilitated in either chronic WAD (local TSP: n = 4, 90 patients and 87 controls; SMD = .68 [-.62 to 1.99]) (remote TSP: n = 8, 254 patients and 214 controls; SMD = .18 [-.12 to .48]) or chronic NSNP (local TSP: n = 2, 139 patients and 92 controls; SMD = .21 [-1.00 to 1.41]), (remote TSP: n = 3; 91 patients and 352 controls; SMD = .60 [-1.33 to 2.52]). ⋯ PERSPECTIVE: This review and meta-analysis present the current evidence on CPM and TSP in patients with WAD and NSNP. Standardization of measurement methodology is needed to draw clear conclusions. Subsequently, future studies should investigate the clinical relevance of these measurements as prognostic variables or predictors of treatment success.