HCV is the most common cause of chronic liver disease and the most common indication for liver transplantation in the United States. Hepatitis С is more common in African Americans than Caucasians, with a seroprevalence of 3.2% in non-Hispanic African Americans and 1.5% in non-Hispanic Caucasians. In addition, 96% of African Americans with HCV have genotype-1 infections. The latest treatment option for chronic HCV includes combination pegylated interferon. The likelihood of a sustained virological response (SVR) to treatment, defined as an undetectable viral load six months after therapy, correlates with several clinical and viral factors, including age, genotype, histology and initial level of HCV RNA in serum. Recently completed trials of pegylated interferon and ribavirin treatment in chronic HCV report that patients with genotypes 2 and 3 have up to an 80% SVR, while those with genotype 1 have a 40% SVR overall.
Several studies have demonstrated a marked disparity in racial responsiveness to treatment since the advent of interferon-based therapy. African Americans with chronic HCV had significantly lower SVR rates to interferon monotherapy, which was overcome by combination therapy with ribavirin in one study. The most recent study, which evaluated the role of race in responsiveness to pegylated interferon and ribavirin, still demonstrated that African Americans had a lower rate of SVR compared with non-Hispanic whites—a difference that could not be explained by genotype alone.
The role of race in treatment responsiveness is further complicated by the fact that African Americans are predominantly genotype 1, while Caucasians and other non-African-American racial groups are a mixture of different genotypes. The purpose of our study was to determine whether the predominance of genotype 1 among African Americans could completely account for the lower response rates to pegylated interferon and medication ribavirin, or whether there are other less clearly identified factors intrinsic to race that account for differences in response between different populations.