Predictive Value of Gamma-Glutamyl Transferase Levels for Contrast-Induced Nephropathy in Patients With ST-Segment Elevation Myocardial Infarction Who Underwent Primary Percutaneous Coronary Intervention

Contrast-induced nephropathy (CIN) after primary percutaneous coronary intervention (PPCI) is associated with adverse short- and long-term outcomes. The aim of this study was to evaluate the predictive value of gamma-glutamyl transferase (GGT) for risk of CIN in patients with ST-segment elevation myocardial infarction who underwent PPCI. A total of 473 patients were enrolled in the study. A relative increase in serum creatinine ≥25%, or an absolute increase ≥0.5 mg/dl, from the baseline within 72 hours of contrast exposure was defined as CIN. Patients were divided into 3 groups according to GGT tertiles (tertile 1, GGT <19 U/L; tertile 2, GGT 19 to 33 U/L; and tertile 3, GGT >33 U/L) on admission. Demographics, clinical risk factors, laboratory parameters, CIN incidence, and other inhospital clinical outcomes were compared among GGT tertiles. CIN incidence was significantly higher in tertile 3 (29%) compared with tertiles 1 (11%) and 2 (11%, p <0.001). Inhospital death incidence was significantly increased across tertiles (from tertile 1 to tertiles 2 and 3, 1%, 4%, and 5%, respectively, p <0.05). In receiver operating characteristic analysis, a threshold value of GGT >26.5 U/L had 70% sensitivity and 60% specificity for CIN. After including variables found significant in univariate analysis, the presence of diabetes mellitus (odds ratio [OR] 1.71, 95% confidence interval [CI] 1.22 to 2.31, p <0.001), C-reactive protein (for each 1 mg/L increase; OR 1.01, 95% CI 1.00 to 1.02, p = 0.007), contrast volume (for each 1-ml increase; OR 1.01, 95% CI 1.00 to 1.02, p = 0.012), and GGT >26.5 U/L (OR 2.59, 95% CI 1.48 to 4.53, p <0.001) were found as independent associates of CIN in multivariate regression analysis. Each 1 U/L increase in GGT was also associated with CIN risk (OR 1.04, 95% CI 1.03 to 1.06, p <0.001). In conclusion, GGT on admission was a significant and independent predictor of CIN after PPCI in patients with ST-segment elevation myocardial infarction.