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

Objective: Discontinuation of metformin treatment is a frequently used approach in clinical practice in diabetic ST-segment elevation myocardial infarction patients using metformin in order to reduce the risk of contrast-induced acute kidney injury. There is insufficient evidence in the literature to support this approach. The aim of this study is to determine whether the risk of contrast-induced acute kidney injury is different in diabetic ST-segment elevation myocardial infarction patients using metformin compared to those not taking metformin.

Methods: The population of the study consisted of patients who applied to our centers that are covered by this study with the diagnosis of ST-segment elevation myocardial infarction and underwent primary percutaneous intervention between 2014 and 2019. Three forty-three diabetic patients that met the study inclusion criteria were divided into 2 groups as who have been receiving metformin and who have not. Patients' creatinine values at admission and peak creatinine values were compared in order to determine whether they have developed contrastinduced 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.