Objective: It is unclear whether co-infection with hepatitis C virus (HCV) can influence HIV related morbidity or mortality, either by accelerating HIV-related disease progression, or by contributing to end stage liver disease. The aim of this study was to examine the effect of HCV infection on the severity and progression of HIV disease in a cohort of Edinburgh intravenous drug users (IDUs).
Methods: In 240 (47%) out of 508 patients in the Edinburgh IDU cohort both HIV seroconversion dates and anti-HCV serology were available. Demographic variables and HIV-related progression between anti-HCV positive and anti-HCV negative groups were compared. Parameters assessed included clinical endpoints (time of development of significant symptoms attributable to HIV (CDC stage IV), time of development of AIDS, and time of death) and immunological endpoints (time of CD4+ counts dropping below 200/mm3, 100/mm3 and 50/mm3).
Results: Two hundred and two out of 240 patients (84%) had positive anti-HCV serology. There was no significant difference in the frequency of clinical and immunological endpoints between the anti-HCV positive and negative groups. Progression analysis from HIV seroconversion to HIV related clinical endpoints indicated that anti-HCV serology was not a significant factor influencing the rate of HIV progression (relative risks (RR) for anti-HCV positive group: seroconversion to CDC IV, 1.01; seroconversion to AIDS, 1.05; seroconversion to death, 0.90). Likewise, HCV serostatus did not significantly affect progression to immunological endpoints (RR for anti-HCV positive group: seroconversion to CD4+ < 200/mm3, 1.04; seroconversion to CD4+ < 100/mm3, 1.13; seroconversion to CD4+ < 50/mm3, 0.97. Overall mortality from end stage liver failure was 4% in HCV-seropositive patients without AIDS. This suggests that HCV has had a clinically (though not statistically) significant impact on overall survival in this cohort.
Conclusions: This study demonstrates that HCV co-infection does not influence the rate of progression to either clinical or immunological endpoints in our population of HIV-infected drug users. Further data are required to assess the effect of HIV on thge progression of HCV-related liver disease.