The impact of joint disease on the Modified Health Assessment Questionnaire scores in rheumatoid arthritis patients: A cross-sectional study using the National Database of Rheumatic Diseases by iR-net in Japan

Objectives: To investigate the effect of bilateral and unilateral joint disease on the Modified Health Assessment Questionnaire (MHAQ) scores and the differences in joint weighting in rheumatoid arthritis patients. Methods: A total of 9212 subjects from the Japanese nationwide cohort database NinJa, 2011, were analyzed. The presence or absence of disease in each joint, including swelling and/or tenderness, was investigated. The correlations between bilateral and unilateral disease in each joint and MHAQ scores were investigated using multivariable logistic regression analysis. Results: The patients' mean age and disease duration was 63.2 and 12.2 years, respectively. The Disease Activity Score-28 was 3.3. The odds ratios of physical impairment according to the MHAQ using multivariable logistic regression models for bilateral and unilateral joints, respectively, were: shoulder, 4.0 and 1.8; elbow, 2.6 and 1.8; wrist, 1.9 and 1.5; hip, 1.7 and 3.0; knee, 2.6 and 1.9; ankle, 2.3 and 2.0, finger, 1.4 and 1.2; and toe, 1.0 and 1.1. The shoulder, elbow, wrist, knee, and ankle had a significant effect on physical impairment. Conclusions: The MHAQ score was significantly affected by shoulder, elbow, wrist, knee, and ankle joint disease. Furthermore, bilateral disease tended to have a greater effect on physical impairment than unilateral disease.