Effect of continuous use of metformin on kidney function in diabetes patients with acute myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND: Diabetes patients presenting with ST-segment elevation myocardial infarction (STEMI) scheduled for primary percutaneous coronary intervention (PCI) have an increased risk of contrast induced-acute kidney injury (CI-AKI). The effects of continuous use of metformin on kidney function are still controversial in patients submitted to primary PCI. This study aimed to assess continuous metformin therapy on kidney function in diabetic patients undergoing coronary intervention. METHODS: Two hundred eighty-four patients with metformin-treated diabetes, who underwent coronary intervention within 24 h for STEMI, were enrolled in the retrospective study. All the patients had estimated glomerular filtration rate (eGFR) of > 30 mL/min/1.73 m(2). According to the physicians’ decisions after admission, 119 patients continued metformin treatment after primary PCI, while 165 patients discontinued it > 48 h after the procedure. Serum creatinine was collected at admission and within 48 h post primary PCI to evaluate the incidence of CI-AKI. We performed a multiple logistic regression analysis to examine the determinants of CI-AKI. RESULTS: No statistical difference in CI-AKI incidence between the continuous and the discontinuous metformin group (12.6%vs10.3%, p = 0.545). Multivariable logistic regression analysis indicated eGFR ≤60 ml/min/1.73 m(2)[p = 0.025, OR: 3.131; 95% CI (1.156–8.482)] and contrast volume [p = 0.002, OR: 1.010; 95% CI (1.004–1.016)] were predictive factors of CI-AKI. Metformin therapy was irrelevant to CI-AKI [p = 0.365, OR: 0.698; 95% CI (0.320–1.521)]. No case of lactic acidosis was found in this study. Besides, the study supported discontinuation of metformin was not beneficial for patients’ blood glucose control after admission. CONCLUSIONS: The study indicated that the metformin continuation after primary PCI for STEMI in diabetic patients with eGFR > 30 ml/min / 1.73 m(2) did not increase the risk of CI-AKI.