Coinfection with hepatitis C virus does not hasten HIV disease progression, according to a retrospective analysis of data gathered in the pre-HAART era and published in the May edition of HIV Medicine. Investigators from the CAESAR study also found that injecting drug use and abnormal liver function were the strongest predictors of HCV coinfection, and that few gay men appeared to have been infected with HCV through sex.
The CAESAR study was an international, multicentre, randomised trial into the safety and efficacy of the addition of 3TC into an antiretroviral treatment regimen of either AZT monotherapy or AZT and ddC dual therapy. The trial was conducted in the early 1990s before the availability of HAART, and enrolled individuals with CD4 cell counts between 25-250 cells/mm3 in Canada, Australia, Europe and South America.
Given the increasing importance of HCV as a cause of illness and death in HIV-positive individuals since the advent of HAART, the CAESAR investigators conducted a retrospective analysis to establish the prevalence of HCV coinfection in their cohort, predictors of HCV coinfection, and if HCV hastened HIV disease progression.
Of the 1649 patients tested for HCV at baseline, a total of 265 had HCV antibodies, giving an overall coinfection rate of 16.1%. However, the investigators noted that there were considerable regional variations in the prevalence of HCV coinfection from a low of 1.6% in South Africa to a high of 48.6% in Italy. A total of 9.2% of the CAESAR study participants were coinfected with HCV in the UK, over 20% of individuals were coinfected in Sweden, France, and Switzerland, and over 40% in Spain.
Coinfection did not influence HIV disease progression. Median changes in CD4 cell count (HIV patients 6 cells/mm3, coinfected patients 4 cells/mm3), and progression to new AIDS-defining illness (HIV 13%, HIV/HCV 11%), were similar in the year following entry to the study.
Prevalence of coinfection differed markedly according to HIV risk group. The group with the lowest prevalence of coinfection was gay men (3.4%), rising to 44.4% for gay men with a history of injecting drug use, 52.9% for individuals who were infected with HIV by blood products, and 92.7% for injecting drug users.
The strongest association with coinfection was for exposure category (p<0.001). Compared to gay men, injecting drug users had an odds ratio of coinfection of 365 (95% confidence interval: 179-742). A history of injecting drug use and ALT level above 40U/L at baseline had a positive predictive value of 35% for HCV coinfection, a negative predictive value of 96%, a sensitivity of 82% and specificity of 71%.
”A combination of country-specific HIV/HCV coinfection prevalence, HIV exposure category and baseline ALT level was highly predictive of HIV/HCV coinfection”, comment the investigators. Although they endorse HCV testing for all HIV-positive individuals, they recommend that HCV testing should be particularly targeted at individuals with a history of injecting drug use or who have abnormal liver function.
The investigators also comment that the 3% coinfection rate seen in gay men “supports low efficiency of sexual transmission of HCV.” However, they note that recent studies have recorded a large number of acute HCV infections amongst HIV-positive gay men whose only risk activity was sex.
Regarding the impact of HCV on HIV disease progression, the investigators conclude, “our study, performed in the pre-HAART era, suggests that HCV has no significant impact on HIV disease progression.”
Further information on this website
Hepatitis C - overview
Hepatitis C - factsheet
HIV and hepatitis - booklet in the information for HIV-positive people series (for a free copy of the 2004 edition email info@nam.org.uk)
References
Amin J et al. HIV and hepatitis C coinfection within the CAESAR study. HIV Medicine 5: 174-79, 2004.