An Observational Analysis of a Large Cohort of Pneumocystis jirovecii Pneumonia

Abstract

Background Pneumocystis jirovecii pneumonia (PCP) is increasingly seen in patients who are non-HIV immunocompromised hosts, yet modern risk factors and outcomes are poorly recognized and defined. Methods A retrospective review was conducted of adult patients who met criteria for proven or probable PCP from 2017 to 2024 across a large academic multicenter health system. The primary outcome was mortality among cohorts, defined by etiology of immunosuppression through univariate and age-adjusted logistic regression. Secondary analyses included trends in annual diagnoses and testing patterns. Results A total of 701 patients met criteria for inclusion, representing one of the largest clinically characterized cohorts of PCP to date. The median age was 65 years (IQR, 54-73) and 62% were male. The most common risk groups were hematologic malignancy (32.2%), solid tumor cancers receiving chemotherapy (22.4%), and autoimmune disease with immunosuppression (17.7%). Annual PCP diagnoses increased at a rate of 15.8% (95% CI, 8.9%-23.2%) in parallel with increased testing. Only 5.4% of patients were receiving prophylaxis at the time of diagnosis. Overall mortality was 20% (95% CI, 17%-23%) and highest in cirrhosis (adjusted odds ratio, 6.24; 95% CI, 2.84-13.69; P