Metformin and CI-AKI Risk in STEMI: Evaluation Using Propensity Score Weighting Method

Objective: Discontinuation of metformin therapy is a frequent clinical practice to reduce the risk of contrast-induced acute kidney injury (CI-AKI) in diabetic ST-segment elevation myocardial infarction patients using metformin. There is insufficient evidence in the literature to support this approach. The aim of this study is to determine whether the risk of contrastinduced acute kidney injury is different in diabetic ST-segment elevation myocardial infarction patients using metformin compared to those not taking metformin. Methods: The study population consisted of patients with ST-segment elevation myocardial infarction admitted to the centers that participated in this study between 2014 and 2019 and underwent primary percutaneous intervention. Diabetic patients (n = 343) that met the study inclusion criteria were divided into 2 groups as who have been receiving metformin and who have not. Patients' creatinine values on admission and peak creatinine values were compared in order to determine whether they have developed contrast-induced acute kidney injury. The 2 groups were compared using conditional logistic regression analysis conducted with the inverse probability weighting method. Results: Non-weighted classic multivariable logistic regression analysis revealed that metformin use was not associated with acute kidney injury. Weighted conditional multivariable logistic regression revealed that the increase in the risk of acute kidney injury was associated with baseline creatinine levels [odds ratio: 1.49 (1.06-2.10; 95% CI) P = .02] and that the increase in the risk of contrast-induced acute kidney injury was not associated with metformin usage [odds ratio: 0.92 (0.57-1.50, 95% CI) P = .74]. Conclusion: No statistically significant difference was found between the metformin and nonmetformin users among the diabetic ST-segment elevation myocardial infarction patients who underwent primary percutaneous intervention in the risk of contrast-induced acute kidney injury.