Urea to Albumin Ratio Is an Independent Predictor of In-Hospital Mortality in Patients With Severe Pneumonia: A Retrospective Cohort Study

Background: Severe pneumonia (SP) is a major complication of respiratory system disease that is associated with high mortality and morbidity. Our objective was to identify risk factors predictive of SP patients and its mortality in intensive care unit (ICU). Methods: We conducted a single-center retrospective observational study involving 212 patients with SP in ICU from June 1st, 2016 to June 1st, 2020. The receiver operating characteristic (ROC) curve was constructed to assess the predictive significance of urea to albumin ratio (U/A). Kaplan-Meier survival curves were plotted with log-rank tests to compare survival of patients with different value of U/A. Multivariate COX regression models were used to calculate the adjusted hazard ratios (HR). Additionally, interaction analysis showed the association between U/A and in-hospital mortality was influenced by sex. Primary outcome was in-hospital mortality. Results: A total of 212 patients were enrolled in the analysis. In the hospital, 101 (47.6%) patients had died. ROC analysis showed that the current cut-off of 0.2555 had a sensitivity of84.2% for in-hospital mortality (AUC = 0.63, 95%CI: 0.55-0.70,P = 0.001). The multivariate COX analysis showed that the incidence of death was higher with the higher U/A group than the lower group (HR: 2.234, 95%CI: 1.146-4.356, P = 0.018).Besides, this pattern persisted in subgroup analyses considering sex. (HR: 9.380, 95%CI: 2.248-39.138, P = 0.002) Conclusions: A high level of U/A is an independent risk factor for in-hospital mortality in patients with SP.