Serum sialic acid as a marker of alcohol consumption:: Effect of liver disease and heavy drinking

Background: Serum sialic acid (SA) has been suggested as a new marker of alcohol consumption, There are, however, only a few studies on the clinical value of such measurements. The relationship between serum SA and liver disease is also unknown. Methods: We determined serum SA concentrations in a sample of 51 alcoholics and 20 healthy controls by using high-performance liquid chromatography with an anion-exchange column and pulsed amperometric detection. The alcoholic sample included 32 patients with liver disease, the severity of which was assessed by previously established combined clinical, laboratory, and morphological indices. In addition, there were 19 heavy drinkers without significant liver disease despite a well documented history of excessive alcohol consumption. Results: The (mean +/- SD) SA concentrations (1.449 +/- 0.3019 mmol/liter) were significantly higher in the alcoholics than in the healthy controls (1.154 +/- 0.1702 mmol/liter). With the optimal cutoff limit for serum SA (1.425 mmol/liter), a specificity of 1.00 and sensitivity of 0.51 were obtained. The diagnostic accuracy of serum SA according to receiver operating characteristic analysis was good, with the area under the curve being 0.805 (0.052). Unlike the traditional serum markers of alcohol consumption (gamma-glutamyl transferase, carbohydrate-deficient transferrin, and aspartate amino transferase), serum SA was not found to be different between the alcoholics with or without liver disease. Conclusions: Our study suggests that serum SA is a sensitive marker of excessive alcohol consumption. Such measurements may also prove to be of value in conditions in which the results of the traditional markers reflect the severity of liver disease rather than alcohol consumption.