Cardiovascular disease is a growing concern as people with HIV live longer thanks to effective antiretroviral therapy. Several studies have shown that HIV positive individuals are at higher risk for heart disease, whether due to antiretroviral therapy or the effects of the virus itself.

A new study presented last week at the XVII International AIDS Conference in Mexico City suggests that HIV positive people coinfected with hepatitis C virus (HCV) may have an additional risk factors for cardiovascular problems such as heart attacks and strokes. This may be the case even though HCV infection is associated with a lower likelihood of elevated blood lipids that contribute to atherosclerosis.

Roger Bedimo and colleagues analyzed data from the Veterans Administration Clinical Case Registry -- which includes more than 20,000 HIV positive patients, about one-third of whom also have HCV -- looking at the impact of HIV-HCV coinfection on risk of acute myocardial infarction (MI; heart attack) and cerebrovascular disease (stroke). They also compared the risk of these events in the pre HAART (1980 to 1995) and the HAART (1996 to 2004) eras.

A heart attack or acute myocardial infarction (MI) occurs when one of the arteries that supplies the heart muscle becomes blocked.

Results

• HIV-HCV coinfected patients were less likely to have abnormally high blood lipid levels or to be taking lipid-lowering medications than those with HIV alone:

• 18% of coinfected patients had total cholesterol above 240 mg/dL, compared with 27% of people with HIV alone.

• 55% of coinfected individuals had triglyceride levels above 200 mg/dL, compared with 60% of HIV monoinfected people.

• Individuals with HIV alone had an increased likelihood of having high cholesterol after the advent of HAART (rising from 24% to 31%), but the rate did not change among coinfected patients.

• The likelihood of having high triglycerides decreased in both groups in the HAART era.

• In general, traditional risk factors such as older age, diabetes, and high blood pressure predicted an increased risk of acute MI or stroke, except that smoking -- unexpectedly -- was not associated with an elevated risk of heart disease and had a slight protective effect against stroke.

• In the pre-HAART era, HIV-HCV coinfection was associated with about a 40% higher risk of acute MI or stroke.

• In the HAART era, rates of acute MI were 3.36 per 1000 person-years (PY) for individuals with HIV alone and 4.19 per 1000 PY for coinfected patients.

• This represented a 25% increased risk after adjusting for other factors, but did not attain statistical significance (P = 0.072).

• For stroke in the HAART era, the rates were 11.12 per 1000 PY for HIV monoinfected people and 12.47 per 1000 PY for coinfected individuals.

• This represented a 20% increased risk, which was statistically significant (P = 0.013).

Based on these findings, the researchers concluded that HIV-HCV coinfection "was associated with a significantly increased risk of acute MI and cerebrovascular disease in the pre-HAART era." However, they added, "This effect appears to decline in the HAART era for acute MI, but not for cerebrovascular disease."

They recommended that "adjustment for HCV status is indicated" when assessing cardiovascular disease risk in people with HIV.

VA North Texas Health Care System, Medicine, Dallas, TX; University of Alabama at Birmingham, Medicine, Birmingham, AL; University of Texas Southwestern Medical Ctr, Medicine, Dallas, TX.

8/15/08

Reference
R Bedimo, A Westfall, M Mugavero, and others. HCV co-infection and risk of acute myocardial and cerebrovascular disease among HIV-infected patients in the pre-HAART and HAART eras. XVII International AIDS Conference (AIDS 2008). Mexico City. August 3-8, 2008. Abstract THAB0205.