Consolidation Volume Assessed by Quantitative Computed Tomography Predicts the Prognosis of Pneumocystis Pneumonia in Rheumatic Diseases

Objective To investigate the prognostic value of quantitative computed tomography (QCT) analysis in pneumocystis pneumonia (PCP) patients with rheumatic diseases, specifically relating abnormal lung volumes (ALV) to major clinical events (MCE). Methods This multicentre, retrospective study included 83 PCP patients with rheumatic diseases. QCT automatically quantified ALV, categorised into consolidation (≥ -300 HU) and ground-glass opacities (< -300 HU). The primary outcome was MCE, including intubation, intensive care unit admission and death. Logistic regression and survival analyses assessed associations between QCT-derived volumes and MCE. Results MCE occurred in 17 patients (20%). Patients with MCE had significantly larger consolidation volumes than those without MCE (median, 5.7% vs 0.4%, p < 0.001). Logistic regression analysis identified lactate dehydrogenase, C-reactive protein, and beta-D-glucan as risk factors; however, consolidation volume remained independently associated with MCE after adjustment (odds ratio: 1.33, 95% confidence interval 1.11-1.59, p < 0.001). Receiver operating characteristic analysis of consolidation volume for predicting MCE showed an area under the curve of 0.89 (p < 0.001). Kaplan-Meier analysis revealed significantly lower MCE-free survival in patients with consolidation volumes ≥ 1.4% (p < 0.001; log-rank test). Conclusion In PCP patients with rheumatic diseases, QCT-derived consolidation volume is a strong predictor of severe outcomes.