A meta-analysis of over 30 studies involving in excess of 100,000 patients with HIV has shown that hepatitis C co-infection does not increase the risk of progression to AIDS. The study is published in the November 15th edition of Clinical Infectious Diseases, and is now available online.
However, the researchers did find that in the period since effective anti-HIV treatment became available, co-infected patients still have a 35% higher risk of death compared to patients who only have HIV. The investigators believe that that “the major contributor to mortality among coinfected subjects during the HAART [highly active antiretroviral therapy] era is likely to be liver disease.”
Antiretroviral therapy means that many people with HIV can look forward to a long and healthy life. However, the predicted prognosis of individuals co-infected with HIV and hepatitis C is significantly shorter than that of patients who are infected with HIV alone..
Indeed, liver-related disease is now an important cause of death in HIV/hepatitis co-infected patients. Although there is a lot of evidence showing that HIV accelerates the course of hepatitis C disease, there is less agreement about the effect of hepatitis C on HIV disease progression.
A team of US investigators therefore conducted a meta-analysis of 37 studies published before April 2008 to see what impact hepatitis C had on HIV disease progression and overall mortality.
Ten of the studies were conducted in the era before effective antiretroviral therapy became available. There included 4413 co-infected patients and 10,213 individuals who were only infected with HIV.
These studies showed that before HIV treatment became available, co-infected patients had a modestly reduced risk of HIV disease progression compared to individuals who were HIV-monoinfected.
The investigators then looked at the studies conducted after 1996 when effective antiretroviral therapy first became available. These studies included 25,319 co-infected patients and 61,697 individuals only infected with HIV.
When combined, these studies showed that co-infected patients had a 35% increase in their of death compared to mono-infected patients (95% confidence interval [CI]: 1.11-1.63).
Co-infected patients who were older, or who were taking antiretroviral therapy had an especially elevated risk of death.
Moreover, the longer an individual was living with co-infection, then the greater was their risk of death.
However, the results of the seven studies that only assessed progression to AIDS showed that co-infected and mono-infected patients had an equal risk of this outcome.
Seven studies reported on the impact of HIV disease progression when this was defined as either diagnosis with AIDS or death. These studies showed that co-infected patients had a 49% increase in their risk of progression to these outcomes compared to mono-infected individuals (95% CI: 1.08-2.05).
“The majority contributor to mortality among coinfected subjects during the HAART (highly active antiretroviral therapy) era is likely to be liver disease”, comment the investigators. They emphasise that there was no difference in the risk of progression to AIDS.
“The meta-analysis did not demonstrate increased risks of developing AIDS-defining events among coinfected patients”, conclude the investigators. They recommend that “future studies that attempt to examine mortality among coinfected subjects should attempt to determine the relative contributions of (1) hepatitis C viremia as a surrogate marker for liver disease risk, (2) whether injecting drug use is current…, and (3) whether broader application of hepatitis C treatment positively impacts mortality in coinfected individuals.”
Chen T-Y et al. Meta-analysis: increased mortality associated with hepatitis C in HIV-infected persons is unrelated to HIV disease progression. Clin Infect Dis 49 (10): 1605-1615, 2009.