People with
HIV/hepatitis C virus (HCV) co-infection are between a quarter and a third more
likely to develop cardiovascular disease compared to people of a similar age with HIV
mono-infection, according to the results of a meta-analysis published in the Journal of Viral Hepatitis. Co-infection
increased the risk of stroke by 24% and the risk of heart attack by 33%.

“In this
meta-analysis of 33,723 participants from four cohort studies, HIV/HCV
coinfection was associated with a 24%-33% increased risk of CVD [cardiovascular
disease] compared to HIV monoinfection,” write the investigators. ‘In
coinfected individuals, it has been postulated that both viruses may act
synergistically through persistent inflammatory responses to increase the risk
of CVD.”

There is a
well-established link between HIV infection and CVD, with research suggesting
that the risk is increased by as much as 61% compared to HIV-negative
individuals. People with HCV also have an increased risk of developing CVD.
It has therefore been suggested that HIV and HCV have the potential to act
synergistically and increase the risk of CVD in individuals with co-infection.
Studies examining whether this is the case have yielded conflicting results. To
clarify this question, investigators in the United States performed a meta-analysis
of studies examining the risk of CVD in adults with HIV/HCV co-infection compared to
people with HIV mono-infection. Risk of CVD – coronary heart disease, congestive
heart failure and stroke – was adjusted for traditional risk factors including
sex, smoking, blood pressure, diabetes and LDL cholesterol.

Four cohort
studies (two prospective, two retrospective) met the inclusion criteria. A
total of 33,723 were included in the analysis. The majority were men and mean
age varied between 36 and 48 years. Average follow-up was between 2.3 and 7.3
years. The studies were conducted in the United States, Canada and Spain.

Three of the four
studies reported a significant association between co-infection and CVD risk.
The other study also reported an increased risk, but the association was just
short of significance.

Pooled estimates
indicated that co-infection increased the risk of stroke by 24% (HR = 1.24; 95%
1.07-1.40) and heart attack by 33% (HR = 1.33; 95% CI, 1.06-1.60).   

“In this
meta-analysis of CVD risk among people with HIV, we found an increased risk of
CVD in those with HIV/HCV coinfection compared to HIV monoinfection,” conclude
the authors. “More research is needed to further quantify this association,
determine potential mechanisms that underlie this association and evaluate
whether treatment for HIV and HCV can reduce CVD outcomes.”