Recurrent serious infections in patients with rheumatoid arthritis-results from the British Society for Rheumatology Biologics Register.

Objectives: To establish the rate of recurrent infection in RA patients recruited to the British Society for Rheumatology Biologics Register - Rheumatoid Arthritis. Secondary objectives were to establish whether the organ class of index infection predicted future serious infection (SI).

Methods: Using data from the British Society for Rheumatology Biologics Register - Rheumatoid Arthritis, a prospective observational cohort, we identified patients with at least one episode of SI. Incidence rates of SI, recurrent SI within the same organ class as the index infection and recurrent SI (of any class) were calculated. A Cox proportional hazards model was used to identify predictors of SI.

Results: In total, 5289 subjects with at least one SI contributing 19 431 patient-years follow-up were studied. The baseline annual rate of first SI was 4.6% (95% CI: 4.5, 4.7), increasing to 14.1% (95% CI: 13.5, 14.8) following an index infection. Respiratory infections were the most frequent (44% of all events). Recurrent infections mirrored the organ class of the index infection. Sepsis, increasing age and polypharmacy were significant predictors of infection recurrence in a fully adjusted model. The system class of index infection was associated with the risk of a recurrent event; subjects who experienced sepsis had the highest risk of subsequent SI within 12 months, 19.7% (95% CI: 15.1, 25.7).

Conclusion: Recurrent infections in RA are common. Understanding patterns and predictors of recurrent infection together with the differential infection risk associated with immunosuppressive agents will help personalize RA care, tailor treatment choices better and mitigate against episodes of SI.