Background: Diabetes, gallstones and dyslipidaemia are widespread, metabolically related, disorders that can affect the liver, often in a clinically silent fashion.
Aim: To investigate whether the presence of these disorders may worsen chronic viral disease by inducing additional liver damage, revealed by variations in serum increases of aminotransferase, alkaline phosphatase and gamma-glutamyl-transpeptidase activities.
Patients and methods: This retrospective, cross-sectional study involved 1,195 patients with chronic hepatitis C virus infection: 47.2% chronic hepatitis, 45.2% cirrhosis, and 7.6% hepatocellular carcinoma. 14.9% of patients had enzymatic cholestasis, defined as combined increase of alkaline phosphatase and gamma-glutamyl-transpeptidase. A Log-linear statistical model was applied to the following variables: stages of liver disease, diabetes, cholelithiasis, hypertriglyceridaemia, hypercholesterolaemia, and enzymatic cholestasis.
Results: Log-linear analysis, applied to categorical variables, revealed, for the first time, a three-way interaction between the stages of chronic liver disease, diabetes, and enzymatic cholestasis. Two-way interactions demonstrated that liver disease stages correlated directly to the prevalence of cholelithiasis and inversely to hypercholesterolaemia. Irrespective of the liver disease stage, hypertriglyceridaemia correlated to hypercholesterolaemia.
Conclusions: This study discloses a synergistic liver damaging effect of diabetes and hepatitis C virus. The three-way interaction obtained by our analysis suggests that diabetes is a risk factor for the progression of viral liver disease and that it contributes to disease evolution, at least in part, by induction of cholestasis.