Patients with rheumatoid arthritis report greater physical functional deterioration in lower limbs compared to upper limbs over 10 years

OBJECTIVE: To examine the overall magnitude of change in self-reported physical function over a 10-year period in patients with rheumatoid arthritis (RA), and to compare changes in physical function between the lower and upper limbs. METHODS: Self-reported data on physical function were collected from the patients in the Oslo RA register (ORAR) through mail surveys between 1994 and 2004. The change in overall physical function was measured by the Short Form 36 (SF-36), the Modified Health Assessment Questionnaire (MHAQ), and the Arthritis Impact Measurement Scales (AIMS2). The MHAQ and AIMS2 were used to address activities related to lower and upper limb function. The magnitude of changes was expressed as crude and adjusted changes and standardized response means (SRMs). The analyses were adjusted for age, sex, duration of disease, and number of surgical procedures in the lower and upper limbs. RESULTS: A total of 414 patients [323 (78%) females, mean age 54.9 years and median disease duration 11.6 years] were included in these analyses. The overall physical function measured by AIMS2 physical and MHAQ deteriorated during 10 years. The magnitude of change in physical function was generally worse for activities related to lower limbs (SRM for adjusted changes 0.16-0.27) than upper limbs (SRM 0.06-0.08). During the 10-year follow-up period, 231 patients (56%) underwent orthopaedic surgery because of their RA. Findings were consistent after adjusting for surgical procedures. CONCLUSION: Patient-reported lower limb function deteriorated more than upper limb function over a 10-year period in patients with established RA.