Insulin Resistance Predicts Liver Fibrosis in Patients with Hepatitis C or Non-alcoholic Fatty Liver Disease

In addition to its association with poorer response to anti-HCV treatment insulin resistance has also been linked to more severe liver fibrosis progression both in people with chronic hepatitis C and in those with non-alcoholic fatty liver disease (NAFLD).

As reported in the September 2007 issue of Gut, Italian researchers conducted a study to assess the relative contributions of steatosis, metabolic abnormalities, and insulin resistance on liver fibrosis, and to determine whether different methods of measuring insulin resistance better predicted fibrosis.

The study included 90 patients with chronic hepatitis C and 90 pair-matched subjects with NAFLD. Basal insulin resistance was assessed using the homeostasis model assessment of insulin resistance (HOMA-IR), and was defined as values > 75th percentile of normal. Post-load insulin resistance was measured using the oral glucose insulin sensitivity index (OGIS), and was defined as values < 25th percentile of normal.

Features of the metabolic syndrome were assessed according to the National Cholesterol Education Program Adult Treatment Panel III (ATP III) definition. Data on insulin resistance and metabolic syndrome were correlated with hepatic histopathology.

Results

• The prevalence of basal insulin resistance according to HOMA-IR was 23.3% in chronic hepatitis C patients compared with 57.8% in subjects with NAFLD.

• When assessed using post-load insulin resistance according to OGIS, prevalence increased to 28.8% in patients with hepatitis C and 67.8% in those with NAFLD.

• In a multivariate model adjusting for age, sex, and body mass index, insulin resistance as determined by OGIS was a predictor of severe fibrosis in both chronic hepatitis C and NAFLD patients, independent of steatosis.

• An OGIS value below the 25th percentile cut-off increased the likelihood of severe fibrosis by a factor of 1.5-2.

• OGIS was more sensitive and generally more specific than HOMA-IR for identifying severe fibrosis in patients with either chronic hepatitis C or NAFLD.

Conclusion

Based on these findings, the investigators concluded, "Post-load insulin resistance (OGIS < 9.8 mg/kg/min) is associated with severe hepatic fibrosis in both NAFLD and in chronic hepatitis C patients, and may help identify subjects at risk of progressive disease."

10/12/07

Reference
G Svegliati-Baroni, E Bugianesi, T Bousheral, and others. Post-load insulin resistance is an independent predictor of hepatic fibrosis in virus C chronic hepatitis and in nonalcoholic fatty liver disease. Gut 56(9): 1296-1301. September 2007.

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