Background: 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.
Methods: 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.
Results: 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.
Conclusion: 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.