Differences in treatment outcome for hepatitis C among ethnic groups

Studies of interferon-based therapies for hepatitis C virus (HCV)–infected patients have documented variable response rates according to ethnicity. However, these studies enrolled low numbers of ethnic minorities. Data from two multicenter trials of combination therapy for hepatitis C were analyzed to determine predictors of treatment success. The first trial was a randomized study comparing interferon administered three times weekly with daily administration. Patients in both interferon groups received weight-based ribavirin. The second trial was an observational study of daily interferon and ribavirin. Only treatment-naïve patients were included in the analysis. Ethnicity (used as a nonspecific term to include race) was determined by patient self-report. Sustained virologic response was defined as negative HCV RNA by polymerase chain reaction at 24 weeks after completion of therapy. A total of 661 patients (390 from the randomized trial and 271 from the observational trial) were available for analysis. Sustained virologic response was highest among Asians (61% [22/36]), followed by whites (39% [193/496]), Hispanics (23% [18/79]), and African Americans (14% [7/50]). In a multiple logistic regression model that adjusted for other factors known to affect treatment outcome, including hepatitis C genotype, Asians continued to be more likely to respond to treatment, whereas Hispanics and African Americans were less likely, as compared with whites. Sustained response rates to interferon and ribavirin therapy differ among ethnic groups. Ethnicity appears to be associated with treatment outcomes, even in a model that adjusts for other factors that influence response to therapy.