The association between serious infection and disease outcome in patients with rheumatoid arthritis

The purpose of this study was to study the association between the past history of serious infection (SI) that required hospitalization and the current disease status of rheumatoid arthritis (RA), including disease activity, physical disability, and radiological joint destruction. The history of hospitalized infection was retrospectively analyzed in a cohort of 370 RA patients. The patients were divided into three groups based on the number of SI events (SI = 0, SI = 1, SI ≥ 2). Disease activity score using 28 joints (DAS28), Health Assessment Questionnaire (HAQ), and modified total sharp score (mTSS) adjusted after disease duration or other confounding factors were compared among the three groups. Among the study patients, 7.3 % (27 patients) experienced single SI (SI = 1) and 2.1 % (8 patients) experienced multiple SI events (SI ≥ 2). Compared with patients with no SI (SI = 0), patients with SI (SI = 1 or SI ≥ 2) had increased pulmonary and autoimmune comorbidities and were more frequently treated with glucocorticoids. DAS28 was not different among the groups, while HAQ and mTSS increased with the number of SI. After adjustment, only mTSS adjusted after disease duration remained statistically significantly different between patients with SI = 0 and SI ≥ 2 (p = 0.030). Multiple SI events are associated with advanced physical disability and radiological joint destruction in patients with RA.