Rheumatoid arthritis patients with low baseline Health Assessment Questionnaire scores have a risk of functional disability progression: a post hoc analysis of a nationwide longitudinal cohort in Japan

OBJECTIVES: To determine prognostic factors for the Health Assessment Questionnaire-Disability Index (HAQ-DI) progression in patients with rheumatoid arthritis (RA) in clinical practice. METHODS: We evaluated 388 biological disease-modifying anti-rheumatic drug (bDMARD)-naïve Japanese patients with RA with moderate to high disease activity at study entry after being treated with conventional synthetic DMARDs. These patients were treated according to a treat-to-target (T2T) strategy for one year. The Disease Activity Score in 28 joints-erythrocyte sedimentation rate (DAS28-ESR) and the HAQ-DI were assessed every three months. We also evaluated joint destruction using a modified total Sharp score at baseline and at one year. HAQ-DI progression was defined as the yearly progression of HAQ-DI >0.1. We performed a multiple logistic regression analysis to explore the factors predicting HAQ-DI progression at one year. RESULTS: HAQ-DI progression was observed in 18% of the patients. The multiple logistic regression analysis revealed the independent variables associated with HAQ-DI progression were: DAS28-ESR >5.1 at baseline (odds ratio [OR] 0.31, 95% con dence interval [CI] 0.13-0.74, p=0.0083); HAQ-DI score at baseline <0.5 (OR 2.27, 95% CI 1.22-4.26, p=0.0102); and achievement of low disease activity at 12 weeks (OR 0.42, 95% CI 0.21-0.82, p=0.0112). CONCLUSIONS: Our data suggest that maintaining clinical improvement according to T2T and initiating the treatment at an early stage are important for functional improvement after one year and that patients with low baseline HAQ scores have a higher risk of HAQ disability progression.