Changes to physical function and body composition during the first two years of polymyalgia rheumatica

Abstract

Abstract Objectives To investigate physical function, body composition, and frailty in recently diagnosed polymyalgia rheumatica (PMR) compared with controls. Methods In a prospective cohort study, patients with PMR and age- and sex-matched controls were assessed 3 months after glucocorticoid initiation and 18 months later. Measures included the HAQ-DI, grip strength, gait speed, five times chair stand test, Short Physical Performance Battery (SPPB), maximum limb strength/power, habitual physical activity (by accelerometer), and body composition (by DEXA). Frailty was defined as per Fried’s phenotype. Results Thirty-six participants with PMR and 32 controls were recruited. Participants with PMR had higher HAQ-DI scores (greater disability) than controls at both visits (mean difference 0.33 [p< 0.001] and 0.39 [p< 0.001]). At follow-up, female participants with PMR performed more poorly in the chair stand test (mean difference 3.27 [95% CI 0.69, 5.84] p= 0.02), SPPB (mean difference -1.23 [95% CI -2.01, -0.45] p= 0.003), and gait speed (mean difference -0.24 [95% CI -0.36, -0.12] p< 0.001) than controls. Between timepoints, female participants with PMR had greater decline in gait speed than controls (mean difference -0.13 [95% CI -0.23, -0.03] p= 0.009). No significant differences for change in body composition were found. Pre-frailty rates were higher in participants with PMR than controls (71.2% vs 34.4% (odds ratio 4.7 [p= 0.003]) and 60.7% vs 34.4% (odds ratio 2.9 [p= 0.04]) at the initial and follow-up visits, respectively). Conclusion PMR has a lasting impact on physical function, particularly in females. These findings highlight the need for routine physical function assessments and targeted muscle conditioning measures in PMR management