PT6:05 Susceptibility to pneumocystis jirovecii pneumonia and predisposing disease-modifying antirheumatic drugs in systemic lupus erythematosus: a cohort study from the largest health care system in Taiwan

Objectives Systemic lupus erythematosus (SLE) and other rheumatic and musculoskeletal diseases (RMDs) patients usually require immunosuppressants regularly. Pneumocystis jirovecii pneumonia (PJP) is a critical opportunistic infection among immunocompromised patients. We aimed to utilize the Chang Gung Research Database (CGRD), the database from the largest health care system in Taiwan, to compare the risk of PJP infection between patients with SLE and other RMDs, and to analyze the predisposing conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) in SLE patients.Methods We included 19148 adult patients who were newly diagnosed as either SLE or other RMDs during 2005-2020 from the CGRD. After propensity score matching, 3745 patients per group were followed until December 2022. We compared the PJP infection risk between the two groups utilizing Cox proportional hazards regression adjusting by age, gender, comorbidities, and medications. We further analyzed the predisposing csDMARDs of PJP infection in SLE group. To determine the associations were causal or the result of the disease characteristics that had warranted initiation of csDMARDs, we used Directed Acyclic Graphs to construct a causal model for each of csDMARDs. We included lymphopenia, neutropenia, low C3, low C4, high anti-dsDNA, proteinuria, renal impairment to represent the effect of SLE disease features as confounders.Results The risk of PJP infection was significantly higher in SLE patients compared with other RMDs in multivariable analysis (adjusted HR=2.144, 95% CI 1.463-3.142, p-value