Incidence of Pneumocystis jirovecii Pneumonia and Prophylaxis-Associated Adverse Events Among Patients with Systemic Lupus Erythematosus.

Objective: Pneumocystis jirovecii Pneumonia (PJP) is an opportunistic infection that may affect patients with systemic lupus erythematosus (SLE). The objective of this project was to describe the incidence of PJP among patients with SLE.

Methods: A retrospective cohort analysis of the TriNetX database. Included patients had ≥2 ICD9- CM/ICD10-CM codes for SLE separated by at least 30 days and were new users of mycophenolate mofetil or cyclophosphamide. The incidence of PJP over the first six months of therapy was calculated; adverse events were assessed using incident rate ratios (IRR) and Cox proportional hazards regressions.

Results: A total of 6,017 patients with SLE were identified. Most were female (5,176, 86%) and Black or African American (2,138, 35.5%). Induction medications included mycophenolate mofetil (5,208, 86.6%), cyclophosphamide (505, 8.4%), or both (304, 5.1%); the most common PJP prophylaxis was trimethoprim/sulfamethoxazole (1,126, 18.7%). Five PJP cases were identified over 2,752 person years, one of whom received PJP prophylaxis, for an incidence rate of 1.8 cases per 1000 person years. In adjusted analysis, patients who received prophylaxis had a higher risk of neutropenia (hazard ratio (HR) 2.5, CI 1.4-4.4), leukopenia (HR 1.9, CI 1.3-2.8), nephropathy (HR 1.7, CI 1.4-2.1), and hyperkalemia (HR 1.4, CI 0.9-2.0).

Conclusion: PJP rarely affects patients with SLE undergoing therapy with mycophenolate mofetil or cyclophosphamide; prophylaxis against PJP is associated with adverse events. The majority of patients with SLE and PJP had structural lung disease. These data do not support universal prescribing of PJP prophylaxis for patients with SLE without lung disease.