Usefulness of Gamma-Glutamyl Transferase and Sequential Carbohydrate-Deficient Transferrin for Unhealthy Alcohol Use Screening in Indigenous Communities.

Unhealthy alcohol use (UAU) screening facilitates identification of patients with alcohol use problems for intervention. This study evaluates the usefulness of gamma-glutamyl transferase (GGT) and sequential percentage of carbohydrate-deficient transferrin (%CDT) in community screening for UAU. In two indigenous communities (A and B), liver disease screening data including GGT, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alcohol use disorders identification test (AUDIT) were reviewed. In Community B, residents with high GGT were invited for sequential evaluation including %CDT, AUDIT, ultrasonography, and liver stiffness measurement. With AUDIT score ≥ 8 and ≥ 4 as UAU criteria for male and female genders, we determined the diagnostic performances and validities of GGT and sequential %CDT in detecting UAU. A total of 1755 residents with available GGT, AST, ALT, and AUDIT were reviewed. UAU prevalence ranged from 7.4% to 44% between communities. For sequential evaluation, 79 residents were enrolled in which 57 (72.2%) were classified as UAU. The performances of GGT, AST, ALT, and AST/ALT ratios in detecting UAU were 0.767, 0.66, 0.597, and 0.549, respectively. With a cutoff of GGT ≥ upper normal limit in detecting UAU, the sensitivity, specificity, accuracy, positive (PPV), and negative predictive value (NPV) were 62.5%, 75.5%, 72.1%, 47.4%, and 85.0%. In Community B, among residents with high GGT, %CDT had a performance of 0.684. With a cutoff of 1.72, the sensitivity, specificity, accuracy, PPV, and NPV were 59.6%, 81.8%, 65.8%, 89.5%, and 43.9%, respectively. GGT and sequential %CDT are useful for screening UAU in indigenous communities with high negative and positive predictive values, respectively.