ObjectiveTo investigate the factors influencing 28-day mortality in patients with severe pneumonia complicated by delirium admitted to the intensive care unit (ICU). MethodsA retrospective cohort study was conducted on patients with severe pneumonia and delirium who were admitted to the ICU within 24 hours from the MIMIC-IV database. The demographic, laboratory, disease severity, and treatment-related data were collected. The 28-day mortality was used as the outcome measure. Potential variables were initially screened through univariate analysis, followed by the application of LASSO and multivariate binary logistic regression to identify independent factors associated with 28-day mortality in patients with severe pneumonia and delirium. Receiver operating characteristic (ROC) curve was subsequently plotted. ResultsA total of 5751 patients with severe pneumonia and delirium were included, of whom 1480 died, yielding a 28-day mortality rate of 25.7%. At a lambda (λ) value of 0.01490941, the model error was minimized. The final multivariate logistic regression results identified the following as independent risk factors for 28-day mortality: advanced age, invasive mechanical ventilation, higher Charlson Comorbidity Index score, lower Glasgow Coma Scale score, non-use of sedatives within 24 hours of admission, use of corticosteroids within 24 hours of admission, elevated neutrophil-to-lymphocyte ratio, increased blood urea nitrogen, decreased hemoglobin, elevated international normalized ratio, elevated total bilirubin, and elevated lactate. The area under ROC curve was 0.756 (95%CI 0.742-0.769). ConclusionThe 28-day mortality rate in patients with severe pneumonia complicated by delirium is high and influenced by multiple factors. It is recommended that preventive strategies be considered from multiple perspectives and dimensions.
