Role of gamma-glutamyl transferase (GGT) in diagnosis of impaired glucose tolerance and metabolic syndrome: A prospective cohort research from the Kerman Coronary Artery Disease Risk Study (KERCADRS)

AimsThe important role of raised serum gamma-glutamyl transferase (GGT) for predicting diabetes mellitus and insulin resistance is clear; however relationship between increased level of GGT and impaired glucose tolerance (IGT) is now hypothesized. We aimed to show the importance of GGT measurement in diagnosis of IGT.Materials and methodsTwo hundred persons were randomly selected from the Kerman Coronary Artery Disease Risk Study (KERCADRS), as a population-based study. All participants underwent GGT analysis test, besides measuring risk factors and components of metabolic syndrome (MS).ResultsThe increase in GGT was correlated with increased prevalence of IGT and MS and its different components. In multivariable analysis, a high GGT was positively associated with the presence of IGT after adjustment for age, sex and MS diagnostic criteria. The area under curve (AUC) for GGT was 0.722 for discriminating IGT from normal condition, and 0.847 for discriminating MS from normal status. In ROC curve analysis, the optimal cut-off value for GGT to discriminate IGT from normal condition was 20.5 IU with the sensitivity of 71.6% and the specificity of 66.1%. The best cutoff value for GGT to discriminate MS from normal condition was also 16.5 IU with the sensitivity and specificity of 78.4% and 78.4%, respectively.ConclusionThe measuring GGT can be a sensitive method for early diagnosis and predicting IGT and MS from normal condition. Because this diagnostic test is a low-cost, highly sensitive, accurate and frequently used laboratory test, its measurement is recommended as a useful marker of both IGT and MS.