Incidence of Pneumocystis Jiroveci Pneumonia in Patients With ANCA‐Associated Vasculitis Initiating Therapy With Rituximab or Cyclophosphamide

• Published in: Arthritis care & research (2010) 2024-02, Vol.76 (2), p.288-294
• Main Authors: Nettleton, Elizabeth, Sattui, Sebastian E., Wallace, Zachary, Putman, Michael
• Format: Article
• Language: English
• Subjects: Adverse events; Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis - diagnosis; Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis - drug therapy; Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis - epidemiology; Antineutrophil cytoplasmic antibodies; Atovaquone; Cyclophosphamide; Cyclophosphamide - therapeutic use; Dapsone; Disease prevention; Electronic medical records; Humans; Incidence; Induction therapy; Leukopenia; Nephropathy; Pentamidine; Pneumocystis carinii; Pneumonia; Pneumonia, Pneumocystis - chemically induced; Pneumonia, Pneumocystis - diagnosis; Pneumonia, Pneumocystis - epidemiology; Prophylaxis; Rituximab; Rituximab - adverse effects; Sulfamethoxazole; Trimethoprim; Vasculitis
• ISSN: 2151-464X; 2151-4658; 2151-4658
• DOI: 10.1002/acr.25222

Objective This manuscript assesses the incidence of Pneumocystis jiroveci pneumonia (PJP) among patients receiving contemporary treatment regimens for antineutrophil cytoplasmic antibody–associated vasculitis (AAV) and adverse events associated with PJP prophylaxis. Methods Incident users of rituximab or cyclophosphamide for AAV were identified in the TriNetX electronic health records database from 2011 to 2022. The incidence rates (IRs) of PJP in the first 6 months of induction therapy with rituximab and/or cyclophosphamide and during postinduction maintenance therapy with rituximab were calculated. Cox proportional hazard models were used to estimate hazard ratios (HRs) and confidence intervals (CIs) for the risk of adverse events commonly associated with PJP prophylaxis. Results We identified 1,461 AAV cases who received induction therapy with rituximab (69.7%), cyclophosphamide (18.9%), or both (11.4%). Prophylaxis prescribed within 30 days of induction included trimethoprim‐sulfamethoxazole (30.7%), atovaquone (5.4%), dapsone (3.8%), and pentamidine (0.8%). During induction therapy, 10 cases of PJP were identified (IR 15.0 cases per 1,000 patient‐years); no deaths occurred. In adjusted analyses, those who received prophylaxis had a higher risk of leukopenia (HR 3.1; 95% CI 1.1–8.6), rash (HR 1.9; 95% CI 1.0–3.6), and nephropathy (HR 2.6; 95% CI 1.3–5.1) than those who did not. During rituximab maintenance therapy (n = 709), five cases of PJP were identified (IR 2.1 cases per 1,000 person‐years), one of whom died during the hospitalization associated with a PJP diagnosis. Conclusion Rates of PJP in patients with AAV were lower than previously observed, and few cases occurred during rituximab maintenance therapy. PJP prophylaxis was associated with adverse events.