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People with HIV at higher risk of heart attack

Known cardio risk factors don’t fully explain increased threat of MI

Louise Prime

Tuesday, 05 March 2013

People carrying the human immunodeficiency virus have a significantly higher risk of a heart attack than their HIV-negative peers, research has shown. The US study, published online in JAMA Internal Medicine, showed that recognised cardiovascular risk factors could not explain the 50% increased risk of acute myocardial infarction (AMI) in people with HIV infection.

Authors of the study compared the risk of myocardial infarction in 82,459 HIV-positive and HIV-negative veterans, most of them men, over a median follow-up of 5.9 years. They then looked to see whether any differences in risk of AMI were explained by differences in the two groups’ Framingham risk factors.

They found that HIV infection consistently raised the veterans’ risk of suffering AMI. For every 1000 person-years’ follow up in the 40-49 years age group, 2.0 AMIs occurred in HIV-positive people compared with 1.5 in HIV-negative people; in the 50-59 age group there were 3.9 vs. 2.2; and in the 60-69 age group there were 5.0 vs. 3.3.

Even after adjusting for Framingham risk factors, comorbidities and substance use, veterans who were HIV positive were more likely to suffer an AMI than HIV-negative veterans (hazard ratio 1.48).

Although the risk of AMI was highest in people with HIV-1 RNA levels of at least 500 copies/ml and CD4 cell count <200 cells/ml, even those whose viral load was controlled to below 500 copies/ml of HIV-1 RNA still had a hazard ratio of 1.39 compared with HIV-negative veterans.

The authors said: “Across three decades of age, the mean … AMI events per 1000 person-years was consistently and significantly higher for HIV-positive compared with uninfected veterans.” They said their results could not be generalised to women, because so few were included in this study.

They concluded: “HIV infection is independently associated with AMI after adjustment for Framingham risk, comorbidities and substance use. Unsuppressed HIV viraemia, low CD4 cell count, Framingham risk factors, hepatitis C virus, renal disease and anaemia are also associated with AMI.”

The author of an accompanying commentary said: “Although the cohort studied was almost exclusively male (>97%), the results demonstrate a clear and consistent excess risk of MI (approximately 50% increase) in HIV-positive people across a range of age groups, with the association between HIV status and MI remaining significant when controlled for a number of covariates including traditional cardiovascular risk factors, such as lipids, blood pressure, and smoking status … [we need] further research in women, research into the underlying mechanisms of the increased risk, and the development of specific interventions to reduce the risk of MI in HIV-positive populations.”

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