HCV RNA levels were higher in HIV-infected participants (6.73 log10 copies/mL) than in HIV-uninfected IDUs (6.40 log10 copies/mL; P < 0.0001). We also performed analyses stratified by HIV-1 infection status (Table 2). Among the HIV-1-uninfected participants, the patterns of association were very similar to those observed among all viremic subjects, except that the HCV RNA level was consistently lower for each characteristic examined. Among the 237 HIV-1-infected participants, differences by age, gender, find more and duration of drug use were blunted or absent, but differences between

African-American and white participants were preserved (P = 0.01). Among the participants with detectable virus, 1,669 had a specimen available for viral genotyping and 1,524 (91.3%) of those subjects were successfully genotyped (Table 3). Most participants were infected with an HCV-genotype 1 strain (1a, 69.0%; 1b, 10.0%), but 9.3% were infected with a genotype 2 strain, 10.6% with a genotype 3 strain, and 1.1% TSA HDAC with genotype 4a. Median HCV RNA level did not differ significantly between participants infected with 1a (6.50 log10 copies/mL) and those infected with 1b (6.63 log10 copies/mL; P = 0.11). In comparison to participants who were infected with genotype 1 (median HCV RNA, 6.50 log10 copies/mL), HCV RNA was lower in those infected with genotype

3 (6.34 log10 copies/mL; P = 0.0003) or 4 (6.12 log10 copies/mL; P = 0.03). We observed the lowest median HCV RNA level (5.64 log10 copies/mL) among participants who had detectable HCV RNA, but could not be genotyped. IL28B genotyping was performed for a subset of the participants with CHC (Table 4). Among 347 African-American participants, we observed no differences in viral levels by IL28B genotype. Among 391 European-American IDUs, those with the IL28-CC genotype had a higher median HCV RNA level (6.67 log10 copies/mL) than those with IL28-TT (6.12; P = 0.01); median HCV RNA level among European-American participants with

the IL28-CT genotype was 6.26 log10 copies/mL. Among 88 participants of 上海皓元医药股份有限公司 Hispanic ethnicity, median HCV RNA levels for those with the IL28-CC (6.63 log10 copies/mL) and IL28-TT (6.19 log10 copies/mL) genotypes were similar to those observed in European-American participants, but this difference was not statistically significant among participants of Hispanic ethnicity, which is a much smaller group. Results from the multivariable ordinal logistic regression analysis (Table 5) confirmed the unadjusted findings. HCV RNA levels were higher for older participants, men, and those infected with HIV-1. Compared to African Americans, HCV RNA levels were lower in all other ancestry groups, although this difference did not approach statistical significance for the comparison with Latinos (P = 0.44). Regarding viral genotype, compared to those infected with genotype 1, participants infected with genotype 2 had higher HCV RNA (P = 0.01).