Factors associated with severe disease and in-hospital mortality in children with non-HIV-associated Pneumocystis jirovecii pneumonia: a single-center retrospective cohort study

Objective To identify factors associated with severe Pneumocystis jirovecii pneumonia (PJP) and in-hospital mortality and evaluate their ability to discriminate severe PJP in children without human immunodeficiency virus (HIV) infection. Methods This single-center retrospective cohort study included 61 children with non-HIV-associated PJP admitted between February 2022 and June 2025, including 31 with non-severe and 30 with severe PJP. Univariable and multivariable Firth penalized logistic regression identified factors associated with severe PJP, and receiver operating characteristic curves assessed discrimination. A restricted Firth logistic model explored in-hospital mortality among severe cases. Results Thirty children (49.2%) had severe PJP, and nine (14.8%) died during hospitalization; all deaths occurred in the severe group. Compared with the non-severe group, the severe group had more frequent primary immunodeficiency, fever, dyspnea, and cytomegalovirus (CMV) coinfection; higher D-dimer, lactate dehydrogenase (LDH), procalcitonin, and CT severity scores; and lower albumin, PaO 2 /FiO 2 , and CD4 + /CD8 + T-cell ratios (all P