Factors associated with frailty in Japanese patients with rheumatoid arthritis: results from the Institute of Rheumatology Rheumatoid Arthritis cohort study.

This study aimed to evaluate the prevalence of, and the factors associated with, frailty in Japanese patients with rheumatoid arthritis (RA). Patients with RA enrolled in the Institute of Rheumatology Rheumatoid Arthritis (IORRA) cohort completed self-administered questionnaires, which included the 5-item frailty screening index. Patients were classified as frail, prefrail, or robust based on the 5 components of the frailty screening index. Logistic regression analyses were used to evaluate associations between clinical variables and frailty. Among 3,290 Japanese patients with RA (86.7% female, mean age 62.4 years) who participated this frailty study, 549 (16.7%) patients were categorized as frailty, 2,063 (62.7%) as prefrailty, and 678 (20.6%) as robust. In multivariable models, body mass index (BMI) ≥ 25 kg/m2 (odds ratio [OR] 1.87, 95% confidence interval [CI] 1.41 to 2.47), BMI < 18.5 kg/m2 (OR 1.31, 95% CI 1.00 to 1.71), disease activity scores in 28 joints (DAS28) (OR 1.32, 95% CI 1.18 to 1.47), Japanese version of Health Assessment Questionnaire disability index (J-HAQ) (OR 1.26, 95% CI 1.04 to 1.52), the European Quality of Life-5 Dimensions (EQ-5D) (OR 0.80, 95% CI 0.74 to 0.85), non-steroidal anti-inflammatory drug (NSAID) use (OR 1.59, 95% CI 1.23 to 1.98), and methotrexate (MTX) use (OR 0.75, 95% CI 0.60 to 0.94) were significantly (P < 0.05) associated with frailty. BMI (both overweight and underweight), DAS28, J-HAQ, EQ-5D, NSAID use, and MTX nonuse appear to be associated with frailty in Japanese patients with RA. Key Points • This is the largest study showing the prevalence and the associated factors of frailty in patients with RA. • Maintaining normal BMI appears to be important for preventing frailty in patients with RA. • We confirmed the significant associations of frailty with high disease activity, high degree of disability, and poor health related QOL in Japanese patients with RA. • NSAID use and MTX nonuse were associated with the frailty in Japanese patients with RA, which could be explained by patients' background.