Establishment and validation of risk prediction model for mortality in elderly patients with sepsis during hospitalization

Objective To establish and validate a model that can predict the risk of death during hospitalization in elderly patients with sepsis.

Methods A total of 238 hospitalized patients with sepsis in the Intensive Care Unit of the First Hospital Affiliated to Harbin Medical University from January 2019 to December 2022 were retrospectively included, and they were divided into death group with 68 cases (28.57%) and survival group with 170 cases (71.43%) according to the prognosis during hospitalization as the primary outcome indicator. Multivariate Logistic regression was used to screen the independent risk factors for death during hospitalization in sepsis patients, and a model for predicting the risk of death during hospitalization in sepsis patients was established based on these factors. The performance of the prediction model was evaluated by the receiver operating characteristic (ROC) curve, and the results were expressed by the area under the curve (AUC); external validation was performed based on the clinical data of 176 sepsis patients from January 2016 to December 2018.

Results Univariate analysis showed that when compared with the survival group, the death group had higher ratios of patients aged over 70 years, ratio of injury (AKI) in stage Ⅲ, higher levels of red cell distribution width (RDW), fibrinogen, lactate, blood creatinine, the National Early Warning Score (NEWS) and the quick Sequential Organ Failure Assessment (qSOFA) score, but lower levels of oxygenation index and albumin, and the differences were statistically significant (P < 0.05). Multivariate Logistic regression analysis showed that age over 70 years old (OR=1.426, 95%CI, 1.055 to 1.928), lactate>6 mmol/L (OR=1.436, 95%CI, 1.105 to 1.867), RDW>16% (OR=1.354, 95%CI, 1.080 to 1.698), AKI in stage Ⅲ (OR=1.982, 95%CI, 1.407 to 2.791), and qSOFA score>2 points (OR=1.853, 95%CI, 1.255 to 2.738) were the independent risk factors for death during hospitalization in patients with sepsis (P < 0.05). Based on the regression analysis results, a risk equation for death in patients with sepsis was established, and consistency index (C_index)=-1.694+0.355×age+0.303×RDW+0.362×lactate+0.684×AKI in stage Ⅲ+0.617×qSOFA score. The ROC curve showed that the AUC of C_index for predicting death during hospitalization in patients with sepsis was 0.882 (95%CI, 0.834 to 0.929) with a sensitivity of 83.82% and a specificity of 77.06% by internal validation, and 0.823 (95%CI, 0.757 to 0.889) with a sensitivity of 74.13% and a specificity of 81.36% by external validation.

Conclusion Age, lactate, RDW, AKI staging and qSOFA score are correlated with the risk of death in elderly patients with sepsis, and the model constructed based on these parameters may help predict the risk of all-cause death during hospitalization in elderly patients with sepsis.