Changes to physical function and body composition during the first 2 years of polymyalgia rheumatica.

Abstract

To investigate physical function, body composition and frailty in recently diagnosed polymyalgia rheumatica (PMR) compared with controls. 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. Thirty-six participants with PMR and 32 controls were recruited. Participants with PMR had higher HAQ-DI scores (greater disability) than the 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 the controls. Between timepoints, female participants with PMR had greater decline in gait speed than the 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 the 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). 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.