Abstract: Objective To investigate the influencing factors of in-hospital death in the elderly patients with type 2 diabetes mellitus (T2DM) complicated with severe pneumonia (SP), and to establish a prediction model. Methods A retrospective observational study was conducted on 208 elderly patients with T2DM complicated with SP admitted to Intensive Care Unit of the Second Affiliated Hospital of Naval Medical University from May 2019 to May 2024. The patients were divided into death group and surviving group based on the 28-day survival status during hospitalization. Multivariate logistic regression analysis was used to determine the risk factors for in-hospital death in the elderly patients with T2DM complicated with SP and to construct a prediction model. Receiver operating characteristic (ROC) curve was used to evaluate the predictive efficacy of the model, and Hosmer-Lemeshow (H-L) test was used to evaluate the calibration of the model. Results Among 208 patients, 85 cases died within 28 days of admission (40.87%). The number of T2DM-related complications≥2, high levels of neutrophil-to-lymphocyte ratio (NLR), brain natriuretic peptide (BNP), blood lactic acid,and low level of partial pressure of oxygen (PaO₂)/fraction of inspired oxygen (FiO₂) ratio were the independent risk factors for in-hospital death in elderly patients with T2DM complicated with SP. The area under the curve of the prediction model constructed based on the five risk factors was 0.862, and the sensitivity and specificity were 87.06% and 83.74%, respectively. H-L test showed P=0.112. Conclusions The number of T2DM-related complications, PaO₂/FiO₂ ratio, NLR, BNP and blood lactic acid are influencing factors for in-hospital death in the elderly patients with T2DM complicated with SP. The in-hospital death prediction model for elderly patients with T2DM complicated with SP based on these factors has a high predictive value.

Key words: type 2 diabetes mellitus, severe pneumonia, prognosis, death in hospital, prediction model