Impact of concomitant chronic kidney disease on hospitalised infections and remission in patients with rheumatoid arthritis: results from the IORRA cohort.

Objectives: To investigate the impact of concomitant chronic kidney disease (CKD) on unfavourable clinical events and remission in Japanese patients with rheumatoid arthritis (RA).

Methods: We included 5103 patients with RA and CKD from the Institute of Rheumatology Rheumatoid Arthritis (IORRA) cohort in 2012. CKD stages were classified into four groups: CKD with normal eGFR ≥60 ml/min/1.73 m2 and proteinuria; mild CKD, eGFR ≥45 to < 60; moderate CKD, eGFR ≥30 to < 45; and severe CKD, eGFR <30. We assessed the association between concomitant CKD and the occurrence of unfavourable clinical events or achieving remission during a 5-year observational period.

Results: Of the 5103 patients with RA, 686 (86.6%) had CKD. Concomitant CKD was associated with hospitalised infections [adjusted hazard ratio (aHR) 1.52, 95% confidence interval (CI) 1.07-2.13, p = .02], especially in the moderate to severe CKD group (aHR 1.93, 95% CI 1.12-3.13, p = .02). Of all subjects, 2407 (47.2%) had active RA at baseline and 401 (16.7%) had CKD. Concomitant CKD was also associated with the failure of achieving remission (aHR 0.82, 95% CI 0.68-0.99, p = .04).

Conclusions: Concomitant CKD was a risk factor for hospitalised infections in Japanese patients with RA and failure of achieving remission in patients with active RA.