Reuters Health Information (2010-03-05): Suppression of hepatitis C viral load reduces insulin resistance
Suppression of hepatitis C viral load reduces insulin resistance
Last Updated: 2010-03-05 18:03:20 -0400 (Reuters Health)
NEW YORK (Reuters Health) - Hepatitis C virus (HCV) infection appears to contribute to insulin resistance, new research shows.
While an association between insulin resistance and HCV infection has been noted (see Reuters Health report, Feb. 27, 2008), direct causality has yet to be established, mainly due to multiple confounders and few acute infections in most previous studies, according to the investigators.
The current study, published online February 15 in Clinical Gastroenterology and Hepatology, took a different approach. "Our study evaluated this relationship by asking whether insulin resistance can be reduced with successful clearance or suppression of hepatitis C virus," said Dr. Raymond T. Chung, director of the hepatology service at Massachusetts General Hospital and senior author on the paper.
Dr. Chung and colleagues analyzed improvements in insulin resistance in a subset of patients in the HALT-C trial, an 8-year multicenter effort that aims to determine the benefits of continuing interferon therapy.
The researchers followed 96 patients with advanced hepatic fibrosis who had 24 weeks of pegylated interferon and ribavirin therapy during the lead-in phase of the study. At 20 weeks, they categorized patients into three groups based on HCV RNA levels: 21 complete responders (21.9%), 37 partial responders (38.5%) and 38 non-responders (39.6%).
Controlling for baseline levels, homeostasis model of insulin resistance (HOMA2-IR) levels fell by an adjusted average of 2.23 in complete responders, 0.90 in partial responders, and 0.18 in non-responders (P=0.036). A linear trend accounted for virtually all variations in scores, and multivariate analyses did not reveal confounders.
"The demonstration that clearance of virus with antiviral therapy was associated with the most pronounced reduction, and partial responses of virus were associated with intermediate reductions, supports a direct causal relationship between HCV and insulin resistance," Dr. Chung told Reuters Health by e-mail.
Additional studies are needed to unravel the mechanisms underlying the relationship between HCV and insulin resistance, he added.
Clin Gastroenterol Hepatol 2010.