Prognostic value of gamma-glutamyl transferase in patients with diabetes mellitus and coronary artery disease

Objectives The aim of the study was to investigate the association between gamma-glutamyl transferase (GGT) activity and mortality in patients with diabetes mellitus and coronary artery disease (CAD). Design and methods The study included 1448 patients with diabetes and angiography-proven CAD who underwent percutaneous coronary intervention (PCI). Baseline GGT measurements were available in all patients. The primary outcome was 3-year mortality. Results Patients were divided into 3 groups: a group consisting of patients with a GGT activity in the 1st tertile (GGT ≤ 29.4 U/L; n = 487), a group consisting of patients with a GGT activity in the 2nd tertile (GGT > 29.4–52.5 U/L; n = 479) and a group consisting of patients with GGT in the 3rd tertile (GGT > 52.5 U/L; n = 482). Overall, there were 179 deaths: 46 (11.9%), 49 (12.1%) and 84 deaths (21.4%) among patients of the 1st, 2nd and 3rd GGT tertiles, respectively (adjusted hazard ratio [HR] = 1.25, 95% confidence interval [CI] 1.05–1.49, P = 0.011). Cardiac death occurred in 101 patients: 22 (5.8%), 30 (7.2%) and 49 deaths (12.9%) among patients of the 1st, 2nd and 3rd GGT tertiles, respectively (adjusted HR = 1.23 [0.96–1.58], P = 0.104, with risk estimates calculated per standard deviation increase in the logarithmic scale of GGT). GGT improved the risk prediction of models of all-cause (P = 0.020) but not cardiac (P = 0.135) mortality (P values show the difference in C-statistics between the models without and with GGT). Conclusion In patients with diabetes and CAD treated with PCI, elevated GGT was independently associated with the risk of 3-year all-cause mortality.