Establishment and validation of a prediction model for death during hospitalization in elderly patients with sepsis combined with acute kidney injury

Objective To initially establish a prediction model for death during hospitalization in elderly patients with sepsis combined with acute kidney injury (AKI) and validate it. Methods Clinical data of 378 elderly patients with sepsis combined with AKI treated in The First Affiliated Hospital of Harbin Medical University from January 2019 to December 2023 were retrospectively included. Based on the outcome during hospitalization, they were divided into death group (122 cases, 32.28%) and survival group (256 cases, 67.72%). Multivariate logistic regression was used to screen the independent risk factors for hospitalized death in septic AKI patients, and a prediction model was established accordingly. The model was evaluated using receiver operating characteristic (ROC) curves. Results The results of multivariate logistic regression showed that age＞70 years (OR=1.387, 95%CI: 1.083-1.776), AKI stage Ⅲ (OR=2.006, 95%CI: 1.388-2.899), sequential organ failure assessment (SOFA) score＞10 (OR=1.791, 95%CI: 1.266-2.536), procalcitonin (PCT)＞3.67 ng/mL (OR=1.553, 95%CI: 1.166-2.068), and activated partial thromboplastin time (APTT)＞40 s (OR=1.290, 95%CI: 1.040-1.602) were independent risk factors for all-cause mortality during hospitalization in elderly patients with sepsis combined with AKI (P＜0.05). Based on the results of multivariate analysis, an equation for the risk of in-hospital death (C-index) in patients with sepsis combined with AKI was established, C-index=-1.722+0.327×(age)+0.696×(AKI stage)+0.583×(SOFA)+0.440×(PCT)+0.255×(APTT). The ROC curves showed that the C-index predicted in-hospital death in elderly patients with sepsis combined with AKI with an AUC of 0.876 (95%CI:0.837-0.915), an accuracy of 81.22%, a sensitivity of 78.69% and a specificity of 82.42%. Conclusion The prediction model based on age, SOFA score, PCT, AKI staging, and APTT can help to identify the high-risk group of elderly patients with sepsis combined with AKI at an early stage of death during hospitalization, and then intervene and adjust the treatment strategy at an early stage, which can help to improve the prognosis of patients.