Reuters Health Information (2011-03-03): Antiviral therapy lowers insulin resistance in HCV genotype 1 infection
Drug & Device Development
Antiviral therapy lowers insulin resistance in HCV genotype 1 infection
Last Updated: 2011-03-03 18:04:14 -0400 (Reuters Health)
NEW YORK (Reuters Health) - Resolution of chronic hepatitis C virus (HCV) genotype 1 infection after treatment with peginterferon and ribavirin is associated with improvement in insulin sensitivity among patients with evidence of insulin resistance before antiviral therapy.
However, factors other than medications may be at work, researchers report in the February issue of Gastroenterology.
Dr. Hari Conjeevaram of The University of Michigan, Ann Arbor, and colleagues note that the insulin resistance associated with the condition might result from liver disease, metabolic factors or hepatitis C virus itself. Moreover, the effect of antiviral treatment on insulin sensitivity isn't well known.
They also point out that insulin resistance may affect the progression of liver disease, but it's uncertain "whether insulin resistance is the cause or the effect of worsening liver function or fibrosis."
To investigate, the team studied data from a prospective trial of a 48-week course of combination peginterferon and ribavirin therapy in 341 patients infected with HCV genotype 1.
Insulin resistance was estimated by the homeostasis model assessment index (HOMA2-IR) based on fasting glucose and insulin levels. Using these criteria, 40% had a HOMA2-IR beyond 2 and were deemed insulin resistant at baseline.
Insulin resistance was associated with higher body weight, higher serum triglycerides, and greater degrees of fibrosis and steatosis on liver biopsy. "All of which," say the investigators, "are well-known risk factors for diabetes and insulin resistance."
In the insulin-resistant group, HOMA2-IR values declined on average by 8% at 24 weeks and by 23% by the end of therapy. These results are in line with those of other investigators. The degree of decline in this group didn't differ significantly by virologic response.
Other findings, the team adds, "suggest that improvements in calculated values for insulin resistance are due at least in part to weight loss and the effects of peginterferon and ribavirin treatment, rather than the degree of decline in HCV RNA levels."
But, importantly, they point out, "only patients who ultimately had a sustained viral response had a significantly lower HOMA2-IR at week 24 when compared with baseline, suggesting that viral eradication may affect insulin response to a greater extent than weight loss and simple viral suppression during interferon treatment."
Overall, the researchers conclude that there appears to be "a direct role for HCV in inducing a decrease in insulin sensitivity." The finding, they add, "provides strong support for recommending therapy in patients with chronic hepatitis C and insulin resistance or diabetes."