Prophylaxis for Pneumocystis pneumonia in patients with rheumatoid arthritis treated with biologics, based on risk factors found in a retrospective study

INTRODUCTION Pneumocystis pneumonia (PCP) is one of the most prevalent opportunistic infections in patients undergoing immunosuppressive therapy. In this article, we discuss risk factors for PCP development in patients with rheumatoid arthritis (RA) during the course of biologic therapy and describe a prophylactic treatment for PCP with trimethoprim/sulfamethoxazole (TMP/SMX). We also evaluate the effectiveness and safety of the treatment. METHODS We retrospectively analyzed 702 RA patients who received biologic therapy and compared the characteristics of patients with vs. without PCP to identify the risk factors for PCP. Accordingly, we analyzed 214 patients who received the TMP/SMX biologic agents as prophylaxis against PCP at the start of treatment to evaluate their effectiveness and safety. RESULTS We identified the following as risk factors for PCP: age at least 65 years (hazard ratio (HR) = 4.37, 95% confidence interval (CI) = 1.04 to 18.2), coexisting pulmonary disease (HR = 8.13, 95% CI = 1.63 to 40.0), and use of glucocorticoids (HR = 11.4, 95% CI = 1.38 to 90.9). We employed a protocol whereby patients with two or three risk factors for PCP would receive prophylactic treatment. In the study with 214 patients, there were no cases of PCP, and the incidence of PCP was reduced to 0.00 per 100 person-years compared with that before the procedure (0.93 per 100 person-years). There were no severe adverse events induced by the TMP/SMX treatment. CONCLUSIONS RA patients with two or three risk factors for PCP who are receiving biologic therapy can benefit from safe primary prophylaxis.