Exploring the relationship between underlying pain mechanism 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 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). Responses were used to categorize pain phenotypes as widespread pain with nociplastic features (WPNF), neuropathic, nociceptive, or mixed (neuropathic/WPNF). Following current physical activity guidelines, self-reported physical activity was categorized as active or insufficiently active/sedentary. Applying multivariable logistic regression, participants with no chronic pain had 2.30 higher odds of being physically active when compared to participants with chronic pain. Similarly, participants with neuropathic and nociceptive pain had, respectively, 1.90 and 1.66 higher odds of being physically active compared to individuals with mixed pain. Higher scores on the Fibromyalgia Survey Criteria (operationalized in this study as an indicator of WPNF) was a significant independent predictor of insufficient physical activity (OR = 0.93, p < 0.01). Findings indicate that experience and phenotype of chronic pain, in particular WPNF, are associated with physical inactivity in PwMS. This suggests that assessing pain phenotype may be important to identify individuals at risk of inadequate physical activity and may guide 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 development of behavioral interventions to enhance physical activity in multiple sclerosis.
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