Diagnostic Value of Serum gamma-Glutamyl-Transferase Activity and Mean Corpuscular Volume in Alcoholic Patients with or without Cirrhosis

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Abstract
In an attempt to assess the diagnostic values of serum γ-glutamyl-transferase (GGT) and mean corpuscular volume (MCV) variations as markers of liver disease and of abstinence in alcoholic patients, we compared 174 patients with alcoholic cirrhosis, 175 with noncirrhotic alcoholic liver disease and 67 patients with nonalcoholic cirrhosis. GGT and MCV values were checked three times, the day of admission, 7 days later, and on the last sample available during follow-up (1 to 12 months), and were compared according to the liver disease and abstinence. A decrease of GGT activity during the 1st week of hospitalization was noted in alcoholics with (-9 IU/liter) or without (-13 IU/liter) cirrhosis and not in nonalcoholic cirrhosis (+8 IU/liter), without MCV variations. During follow-up, median GGT activity was strikingly different in abstinent patients with (27 IU/liter) or without (21 IU/liter) cirrhosis and in nonabstinent patients (99 IU/liter and 123 IU/liter, respectively) (p < 0.001). MCV decrease was noted in alcoholics whatever their abstinence or not, contrasting with the absence of decrease in nonalcoholic patients. For the diagnosis of alcoholism in cirrhotic patients, the positive predictive value (PPV) of a GGT or a MCV decrease during the 1st week of hospitalization was 0.82 and 0.78, respectively, and the negative predictive value (NPV) was 0.33 and 0.70, respectively. For abstinence during follow-up, the PPV of a GGT activity < 50 IU/liter was 0.92 and the NPV was 0.65. In multidimensional stepwise regression analysis, the GGT decrease appeared independently associated with initial GGT activity (p < 0.001) and with alcohol withdrawal (p < 0.001) while MCV decrease was only associated with the initial MCV value. GGT and MCV do appear per se as weak indicators of alcoholism during liver diseases. Inversely, the early decrease of serum GGT activity, which is independent of the type of the liver disease, and a frank decrease of MCV during follow-up of out-patients are markers of alcoholism. A persistent decrease of GGT activity to normal or under 2.5-fold normal values is a marker of abstinence in alcoholics with or without cirrhosis.