Association between metformin use on admission and outcomes in intensive care unit patients with acute kidney injury and type 2 diabetes: A retrospective cohort study

Abstract

Purpose: Acute kidney injury (AKI) occurs in more than half of intensive care unit patients. Effective prevention and treatment strategies for AKI remain limited. We aimed to assess AKI-related mortality in patients with diabetes who were metformin and non-metformin users.

Materials and methods: We included patients with AKI and type 2 diabetes (T2DM) from the Medical Information Mart for Intensive Care database. The 30-day mortality, neutrophil-to-lymphocyte ratio, and length of hospital stay were compared between patients with and without metformin prescriptions. We used multivariable Cox proportional hazards regression, propensity score analysis, and an inverse probability-weighting model to ensure the robustness of our findings.

Results: We included 4328 patients with AKI and T2DM (998 and 3330 patients were metformin and non-metformin users, respectively). The overall 30-day mortality was 14.2% (613/4328); it was 15.7% (523/3330) and 9.0% (90/998) for non-metformin and metformin users, respectively. In the inverse probability-weighting model, metformin use was associated with 37% lower 30-day mortality (HR = 0.63, 95% CI: 0.50-0.80, p < 0.0001).

Conclusions: Metformin use may be associated with reduced risk-adjusted mortality in patients with AKI and T2DM. Further randomized controlled trials are needed to clarify this association.

Keywords: Acute kidney injury; Metformin; Mortality; Neutrophil-to-lymphocyte ratio; Type 2 diabetes.