The effect of insulin on 28-day mortality in non-diabetic sepsis patients: a retrospective study

Objective: To evaluate the association between insulin administration and 28-day mortality in non-diabetic patients with sepsis. Methods: A retrospective analysis of 11,289 critically ill patients with sepsis in the MIMIC-IV database was conducted. Propensity score matching (PSM) was employed to balance baseline characteristics between the insulin-treated and untreated cohorts. The primary outcome was 28-day mortality; secondary outcome measures included intensive care unit (ICU) and hospital length of stay (LOS). The association between insulin use and mortality was evaluated via Cox regression analysis, and survival was estimated using Kaplan-Meier curves and log-rank tests. Results: Of the 11,289 non-diabetic patients meeting the inclusion criteria, 1,172 (10.4%) received insulin. After PSM, the final analysis included 2,960 patients (782 in the insulin group and 2,178 in the control group). Baseline characteristics were well-balanced, with standardized mean differences (SMDs) close to zero. Insulin use was significantly associated with a reduced 28-day mortality rate (hazard ratio [HR] 0.63-0.67, p < 0.001), a finding that remained consistent across all subgroups. However, patients receiving insulin therapy had a longer median ICU LOS (5 days vs. 4 days, p < 0.001) and a more extended hospital LOS (12 days vs. 10 days, p < 0.001). Conclusion: Insulin therapy may improve the survival rate among non-diabetic patients with sepsis but does not shorten the duration of hospitalization. Further research is warranted to elucidate the underlying mechanism and validate these findings.