Changes in physical function over time in rheumatoid arthritis patients: A cohort study

Area of Science:

• Rheumatology
• Clinical Medicine
• Rehabilitation Science

Background:

• Rheumatoid arthritis (RA) significantly impacts patients' lives, with self-reported disability being a key outcome.
• Understanding factors influencing disability is crucial for effective RA management.

Purpose of the Study:

• To investigate the associations between self-reported disability and clinical features, muscle strength, and physical performance in RA patients.
• To examine these associations longitudinally across two distinct RA cohorts.

Main Methods:

• Analysis of two independent prospective RA cohorts (North American and Brazilian).
• Assessment of Health Assessment Questionnaire (HAQ), Disease Activity Score (DAS28), muscle strength (handgrip), and physical performance (chair stand, TUG, SPPB) at baseline and follow-up.
• Statistical analyses included t-tests, Mann-Whitney U, Spearman correlations, and generalized estimating equations.

Main Results:

• HAQ scores were associated with DAS28, handgrip, chair stand, TUG, and SPPB in both cohorts.
• Worsening DAS28, handgrip, and chair stand test performance correlated with increased HAQ over time.
• Worse TUG and SPPB performance were associated with increased HAQ in the Brazilian and North American cohorts, respectively.

Conclusions:

• Self-reported disability in RA is closely linked to disease activity, muscle strength, and physical performance.
• Deterioration in clinical factors and objective physical function predicts worsening disability in RA patients.