Risk of pneumonia infection in patients with rheumatoid arthritis treated with TNFis

What is it about?

Certain opportunistic infections appear to occur with increased frequency in patients with RA treated with TNFis. Pneumocystis jirovecii (formally carinii) pneumonia (PJP) is an opportunistic infection previously reported in patients with RA on TNFi therapy. Transmitted via airborne spores, it is not fully known whether the development of symptoms is a result of prior infection from childhood colonisation or infection during immunocompromised states. The aim of our study was to compare the risk of PJP infection in RA patients treated with TNFi to that in RA patients treated with synthetic DMARDs alone. Using data from the British Society for Rheumatology Biologics Register for RA (BSRBR-RA), the risk of PJP was compared between 13 905 TNFi- and 3677 sDMARD-treated patients. Twenty-five possible PJP cases were reported to the BSRBR-RA and 17 cases were validated as definite or probable infections [15 TNFi (14 on drug, 1 with past TNFi exposure), 2 sDMARD]. The absolute risk of PJP was small and the risk for PJP infection in the TNFi-treated patients was not significantly different compared with the sDMARD-treated patients. The median time to PJP infection was 5.8 months after TNFi commencement.

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Why is it important?

Pneumocystis pneumonia is a rare infection with only a small number of cases identified in this large study. This is the first study of its kind regarding PJP infection. To establish whether TNFis are associated with a significantly increased risk of PJP in RA, a much larger sample size is required and therefore future work on this subject should include collaboration with other biologic registers.

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