Similar Negative Effects of Fatigue on Physical Activity in Persons with Rheumatoid Arthritis and Healthy Controls: A Patient-Control Study

Abstract

Background/Purpose: People with rheumatoid arthritis (pwRA) are prone to fall short of the World Health Organization's physical activity (PA) recommendations due to perceived fatigue and pain. Given the high prevalence of fatigue and its impact on health-related quality of life and social participation, this study investigated objectively measured PA patterns and the association between PA and self-reported fatigue in pwRA compared to healthy controls (HC). Methods: In this observational cross-sectional study, pwRA (DAS28 > 2.6) and HC wore a tri-axial accelerometer (ActiGraph wGT3X-BT, ActiGraph LLC) on one ankle for ;;:,:4 days. Accelerometer-based outcomes included vector magni­ tude counts/min (square root of summed sagittal, frontal, and vertical axes' counts/min squared-primary outcome), step count, and time spent in moderate-to-vigorous intensity PA Data were separated by day and time (weekday/weekend; day­ time/evening) to investigate PA patterns. Fatigue severity was assessed using the Fatigue Severity Scale (FSS, 0-7). Asso­ ciations between fatigue, RA status, and PA were examined using multilevel generalized estimating equations models (patient and day-timing as levels). Interactions between RA and fatigue were tested. Manual forward selection identified mul­ tivariable associations adjusted for confounders.