Anti-TNF therapy is associated with an increased risk of serious infections in patients with rheumatoid arthritis especially in the first 6 months of treatment: updated results from the British Society for Rheumatology Biologics Register with special emphasis on risks in the elderly

Methods. Using data from the British Society for Rheumatology Biologics Register, a prospective observational study, we compared the risk of SI between 11 798 anti-TNF-treated patients and 3598 non-biologic DMARD (nbDMARD)-treated patients. Results. A total of 1808 patients had at least one SI (anti-TNF: 1512; nbDMARD: 296). Incidence rates were: anti-TNF 42/1000 patient-years of follow-up (95% CI 40, 44) and nbDMARD 32/1000 patient-years of follow-up (95% CI 28, 36). The adjusted hazard ratio (adjHR) for SI in the anti-TNF cohort was 1.2 (95% CI 1.1, 1.5). The risk did not differ significantly between the three agents adalimumab, etanercept and infliximab. The risk was highest during the first 6 months of therapy [adjHR 1.8 (95% CI 1.3, 2.6)]. Although increasing age was an independent risk factor for SI in both cohorts, there was no difference in relative risk of infection in patients on anti-TNF therapy in the older population. There was no difference in hospital stay for SI between cohorts. Mortality within 30 days of SI was 50% lower in the anti-TNF cohort [odds ratio 0.5 (95% CI 0.3, 0.8)]. Conclusions. These data add to currently available evidence suggesting that anti-TNF therapy is associated with a small but significant overall risk of SI. This must be balanced against the risks associated with poor disease control or alternative treatments.