Abstract
OBJECTIVES: The aim of this study was to identify the risk factors for Pneumocystis jirovecii pneumonia (PCP) in patients with rheumatoid arthritis (RA) and to recommend appropriate disease-modifying antirheumatic drug (DMARD) selection for those at high risk of developing PCP. METHODS: We conducted a retrospective review of patients with RA who were treated with methotrexate or biologic and targeted synthetic DMARDs (b/tsDMARDs). Patients with no chest computed tomography data or those receiving prophylactic sulfamethoxazole-trimethoprim, atovaquone, or inhaled pentamidine were excluded. RESULTS: Among 554 patients who met the inclusion and exclusion criteria, 16 developed PCP. Multivariate logistic analysis revealed interstitial pneumonia as a significant risk factor for PCP (odds ratio: 4.53, 95% confidence interval: 1.51-13.12), whereas salazosulfapyridine (SASP) use was associated with a reduced risk (odds ratio: 0.11, 95% confidence interval: 0.00-0.81). A Kaplan-Meier analysis comparing the cumulative incidence of PCP between propensity score-matched SASP users and nonusers further demonstrated that SASP use reduced the risk of developing PCP. CONCLUSION: Patients with RA complicated by interstitial pneumonia are at a higher risk of developing PCP. Although methotrexate and b/tsDMARDs do not increase the risk of developing PCP, SASP may potentially reduce the risk. A prospective study is warranted to investigate the efficacy and safety of SASP in patients with RA at high risk for PCP.