Outcomes and Trends of Pneumocystis Pneumonia in hospitalized patients with autoimmune diseases: Insights from the National Inpatient Sample

Pneumocystis jirovecii is an opportunistic fungus that can cause life-threatening Pneumocystis jirovecii pneumonia (PJP) in immunocompromised patients. This study compared the incidence, characteristics, and outcomes of PJP-related hospitalizations in patients with autoimmune rheumatic diseases (ARDs) to those in patients with human immunodeficiency virus (HIV) from 2016 to 2021. We identified PJP-related hospitalizations recorded in the National Inpatient Sample (NIS) database between 2016 and 2021. ICD-10 diagnosis codes were used to identify patients with PJP, HIV, ARDs, malignancies, or organ transplants. Patients with both HIV and ARD were classified under the HIV group. This retrospective analysis utilized descriptive statistics and multivariable logistic regression to evaluate the impact of demographics and comorbidities on clinical outcomes. A total of 10,725 hospitalizations with a principal diagnosis of PJP were identified. Patients with ARDs—without concurrent HIV, malignancy, or organ transplant—accounted for 5.2% of PJP-related hospitalizations. Compared to patients with HIV, those with ARDs had a significantly higher in-hospital mortality rate (24.2% vs. 8.7%, p < 0.001), underwent bronchoscopy more frequently (51.8% vs. 36.6%, p < 0.001), had longer length of stay in the hospital (13.97 days vs. 11.51 days, p < 0.001), and had higher cost of care (196,083US$ vs. 136,978US$ p < 0.001). Non-HIV status remained an independent predictor of poor outcomes even after adjustment for confounders. Patients with ARDs face a significantly higher risk of PJP-related mortality and undergo bronchoscopies more frequently compared to those with HIV. Further research is warranted to identify predictive factors and to inform the development of early detection and treatment strategies aimed at improving outcomes in ARD patients with PJP.