Evidence from large US cohort says anti-HIV therapy does not increase heart disease risk

Antiretroviral therapy has a “negligible public health risk” of cardiovascular events, according to a US study published in the March 1^st edition of the Journal of Acquired Immune Deficiency Syndromes. The investigators found that antiretroviral therapy reduced the risk of all-cause mortality, without increasing the risk of hospitalisation because of heart attack or heart bypass surgery.

Investigators from the US Department of Veterans Affairs have previously published evidence obtained from 38,000 HIV-positive patients that treatment with antiretroviral therapy did not increase the risk of cardiovascular disease or stroke. But since these data were published, other studies have suggested a link between treatment with anti-HIV drugs, particularly protease inhibitors, and an increased risk of heart disease.

The Veterans Affairs investigators therefore repeated their study, extending by 2.5 years the period of analysis. Their retrospective analysis included over 41,000 HIV-positive patients who received HIV treatment and care from the Department of Veterans Affairs between 1993 and 2003. As with their previous analysis, the study outcomes were death from any cause, or hospitalisation because of heart attack, coronary bypass surgery, or admission to hospital or death due to serious cardiovascular events or stroke.

Most of the patients (98%) were men, 44% were white and 52% were African American. Just over a quarter had received treatment for cardiovascular disease, diabetes, high blood fats or smoking disease before their HIV diagnosis, with 6% receiving previous treatment for vascular disease.

Patients were followed for an average of four years and there were 17,558 deaths, 1735 admissions to hospital for heart attack or by-pass surgery, and 19,898 occurrences of death or admission for serious cardiovascular events or stroke.

Death from all causes dropped from 21 deaths per 100 patient years in 1995 to five deaths per 100 person years in 2003. Inpatient admissions because of heart attack or bypass surgery did not change over the ten year period of analysis. And death or admission to hospital because of a serious cardiovascular event or stroke fell after potent antiretroviral therapy first became available and continued to fall thereafter.

Factors associated with admission to hospital for serious cardiovascular events were older age and pre-existing vascular disease.

Compared to no treatment, the use of antiretroviral therapy reduced the risk of death, to 0.18 after 72 months (95% CI: 0.15 – 0.23), but the risk of admission to hospital due to serious cardiovascular illness remained unchanged after twelve, 24, 48 and 72 months of anti-HIV treatment.

“Our results continue to be consistent with a negligible public health risk from cardiovascular complications of highly active antiretroviral therapy”, conclude the investigators, who add that the findings “are again consistent with an increasingly powerful survival benefit from [antiretroviral therapy]. This underscores the importance of access to skillful antiretroviral therapy and of treatment risk factors for comorbidity and mortality.”