Prognostic factors for mortality in age-stratified elderly sepsis patients: A retrospective cohort study based on the MIMIC-IV database

Sepsis represents a major cause of death among elderly patients; however, prognostic factors specific to different age strata within this population remain insufficiently characterized. This retrospective cohort study aimed to identify early predictors of mortality in elderly sepsis patients using the MIMIC-IV database. We included 13,461 sepsis patients aged ≥60 years, stratified into younger-old (60-74 years; n = 7618) and older-old (75-90 years; n = 5843) groups. Propensity score matching was applied to balance baseline characteristics, yielding 4657 matched patients per group. Multivariable logistic regression, receiver operating characteristic analysis, and Kaplan-Meier survival curves were employed to assess clinical and biochemical markers for 28-day mortality and to identify age-specific prognostic indicators. These findings underscore the importance of age-stratified prognostic models to guide targeted clinical interventions and potentially improve outcomes in elderly patients with sepsis. Lactate dehydrogenase (LDH) and the PaO2/FiO2 ratio emerged as key mortality predictors in the younger-old group, whereas urea nitrogen and hypoalbuminemia were predominant in the older-old group. Urine output served as a common predictor across both strata, with oliguria associated with a 2.5-fold increase in mortality risk among older patients. While a combination of predictors enhanced prognostic accuracy in younger-old patients, this was not observed in the older-old group, suggesting a greater influence of frailty and comorbidities in advanced age.