TNF Inhibitor Associated Infectious Risk Greatest in First 6 Months Save

The risk of serious infections (SIE) in RA patients given anti-TNF (TNFi) therapy is not static, instead it has been shown to be greatest in the first 6 months of use according to a recent report in Rheumatology. 

Analysis of data collected from the British Society for Rheumatology Biologics Register, a prospective observational study, compared SIE risk in 11,798 TNFi treated RA patients and 3598 receiving non-biologic DMARD (DMARDs).

They observed 1808 rA patients with at least one SIE (TNFi: 1512; DMARD: 296) with a similar Incidence rate - TNFi 42/1000 patient-years vs. DMARD 32/1000 patient-years of follow-up (adjusted hazard ratio 1.2 [95% CI 1.1, 1.5]), with no difference between the adalimumab, etanercept and infliximab.

The risk of SIE was highest during the first 6 months of therapy [adjHR 1.8 (95% CI 1.3, 2.6)]. Increasing age was an additional independent risk factor for SIE in both cohorts.

While there was no difference in hospitalizations between groups, mortality (within 30 days of SIE) was 50% lower in the anti-TNF cohort [odds ratio 0.5 (95% CI 0.3, 0.8)].

Anti-TNF therapy is associated with a small but significant overall risk of SI, especially in the first 6 months when the patient is likely to be more inflammed and have other risk factors adding to infectious risk.  Early close observation of new TNFi starts is advised.