Clinical Characteristics and Prognostic Predictors of Pneumocystis Jirovecii Pneumonia in Patients with and without Chronic Pulmonary Disease: A Retrospective Cohort Study

Objective: Pneumocystis jirovecii pneumonia (PJP) is a severe respiratory infection caused by Pneumocystis jirovecii in immunocompromised hosts. The role of P. jirovecii colonization in the development or progression of various pulmonary diseases has been reported. Our aim was to explore serial change in serum biomarkers and the independent risk factors for mortality in patients with and without chronic pulmonary diseases who developed PJP. Methods: We performed a retrospective study to select patients with Pneumocystis jirovecii pneumonia between January 1, 2012, and December 31, 2021. Information regarding demographics, clinical characteristics, underlying diseases, laboratory tests, treatment, and outcomes was collected. Univariate and multivariate logistic regression analyses were used to identify independent predictors of inhospital mortality. Results: A total of 167 patients diagnosed with PJP were included in the study: 53 in the CPD-PJP group and 114 in the NCPD-PJP group. The number of patients with PJP showed an increasing trend over the 10-year period. A similar trend was observed for inhospital mortality. Independent risk factors associated with death in the NCPD-PJP group were procalcitonin level (adjusted OR 1.08, 95% CI 1.01-1.16, P=0.01), pneumothorax (adjusted OR 0.07, 95% CI 0.01-0.38, P=0.002), neutrophil count (adjusted OR 1.27, 95% CI 1.05-1.53, P=0.01) at 14 days, and hemoglobin level (adjusted OR 0.94, 95% CI 0.91-0.98; P=0.002) at 14 days after admission. The risk factor associated with death in the CPD-PJP group was neutrophil count (adjusted OR 1.19, 95% CI 0.99-1.43; P=0.05) at 14 days after admission. Conclusion: The risk factors for death were different between patients with PJP with and without chronic pulmonary disease. Early identification of these factors in patients with PJP and other underlying diseases may improve prognosis.