Prognostic Significance of BALF Neutrophil Percentage and Hypoxemia in Non-HIV Pneumocystis jirovecii Pneumonia: A Retrospective Cohort Study

Yuan Li,1,2,* Xin Li,1,* Feifan Zhao,1 Qingtao Zhou,1 Yongchang Sun1,* 1Department of Respiratory and Critical Care Medicine, Peking University Third Hospital, Beijing, People’s Republic of China; 2Department of Respiratory Medicine, The Second Clinical Medical College of Beijing University of Chinese Medicine, Beijing, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yongchang Sun, Department of Respiratory and Critical Care Medicine, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, People’s Republic of China, Tel +86 13910979132, Email [email protected] Qingtao Zhou, Department of Respiratory and Critical Care Medicine, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, People’s Republic of China, Tel +86 13426248158, Email [email protected]: The rising incidence of Pneumocystis jirovecii pneumonia (PJP) in patients without human immunodeficiency virus (HIV) infection, coupled with high mortality rates, highlights growing challenges in disease management. However, mortality risk factors in non-HIV PJP remain incompletely defined, particularly in large cohorts. Thus, we aimed to explore the clinical characteristics and mortality risk factors in these patients.Patients and Methods: This study included non-HIV patients with PJP who were hospitalized at Peking University Third Hospital between January 2014 and May 2023. We collected relevant clinical data and performed logistic regression analysis to identify mortality risk factors.Results: This study included 207 participants (127 male and 80 female) with a median age of 57 (interquartile range: 45– 68) years. The 90-day all-cause mortality rate was 15%. Renal transplant recipients accounted for the highest proportion of patients with underlying diseases (34.8%), followed by those with immune-mediated inflammatory diseases (23.7%). In multivariate logistic regression analysis, the percentage of neutrophils in bronchoalveolar lavage fluid (BALF) and a ratio of arterial oxygen partial pressure to fraction of inspired oxygen (PaO2/FiO2) < 300 mmHg were independently associated with 90-day mortality. A neutrophil percentage ≥ 41.5% in BALF effectively identified patients at high risk of death.Conclusion: In non-HIV patients with PJP, the percentage of neutrophils in BALF and PaO2/FiO2 ratio were strong predictors of adverse outcomes. These markers may help clinicians identify high-risk patients and initiate early intensive care intervention.Keywords: neutrophil percentage in BALF, PaO2/FiO2, non-HIV patients with PJP, 90-day mortality