HCV co-infection hastens HIV disease progression, finds US veterans study

HIV-positive individuals who are co-infected with hepatitis C virus have a shorter survival time than individuals who are only infected with HIV, according to US research published in the November 15^th edition of Clinical Infectious Diseases. This finding is in contrast to a study published in 1999 involving the same study population which found that HIV-positive individuals coinfected with HIV did not have poorer survival.

Co-infection with hepatitis C virus has emerged as a major cause of illness and death in HIV-positive individuals since highly active antiretroviral therapy (HAART) brought about significant reductions in morbidity and mortality caused by HIV.

Investigators from the HIV Atlanta Cohort Study (HAVACS) conducted research involving a cohort of HIV-positive individuals in 1999 which found that there was no connection between HIV and hepatitis C virus coinfection and HIV disease progression. Much of the data for this study was obtained in the pre-HAART era. The investigators speculated that the increased survival of HIV-positive patients since effective antiretroviral therapy became available, and the potential for anti-HIV to cause hepatotoxicity might now yield different results.

Accordingly, investigators conducted a retrospective review of the records of their cohort comparing survival time since HIV diagnosis and progression to AIDS, and CD4 cell count gain after starting HAART in patients who were coinfected with HIV and hepatitis C and individuals who were only infected with HIV.

In total, 970 individuals were included in the investigators’ analysis. The prevalence of hepatitis C coinfection was high, at 32%. A total of 76% of patients received HAART at sometime during the study period, and 67% of individuals had been diagnosed with AIDS.

Sex between men was the most common HIV risk group (48%), followed by injecting drug use (24%). The majority of the cohort were black (73%).

Individuals who were coinfected with hepatitis C were significantly more likely to be older, have a history of injecting drug use, and to have never taken HAART (p

The investigators found that patients with co-infection had shorter survival after their HIV diagnosis than did patients only infected with HIV (p = 0.009). Furthermore, the time from receiving an AIDS diagnosis to death was also shorter for patients coinfected with HIV and hepatitis C than individuals who only had HIV infection (p = 0.022).

However the investigators found no difference between co-infected individuals and patients who only had HIV infection in the time it took to progress to AIDS.

After starting HAART both co-infected and HIV-infected patients experienced a similar recovery in CD4 cell count by month 6. However, injecting drug use was independently associated with decreased CD4 T-cell gain.

A longer-term model which considered CD4 cell count gain from the initiation of HAART to the last follow-up visit found no difference between the coinfected patients and the patients with only HIV infection.

The investigators believe that their study has four clinically relevant findings:

• There is a high prevalence of hepatitis C co-infection in their HIV-positive cohort.
• Individuals with hepatitis C co-infection are less likely to receive HAART.
• Co-infection with hepatitis C results in markedly reduced survival from the time of diagnosis with HIV and the time of first AIDS diagnosis.
• Hepatitis C co-infection does not affect short or longer term CD4 cell count recovery after starting HAART.

“These findings demonstrate a shift in the effect of hepatitis C virus coinfection from the pre-HAART era to the HAART era. A previous evaluation of survival in the HAVACS cohort found hepatitis C virus infection had little effect on progression of HIV infection,” write they investigators.

Possible reasons for this change suggested by the investigators include:

• The hepatic side-effects of HAART.
• More patients being tested for hepatitis C, correcting a selection bias.
• The longer duration of follow-up allowed more time for the development of serious hepatic events. However, this is unlikely as there was no significant increase in mortality rates for liver disease after 1997.

“The high prevalence of hepatitis C virus coinfection in this cohort and the accelerated progression to death underscore the importance of this secondary infection, now and in the future,” say the authors