HIV-positive patients have high prevalence of asymptomatic heart disease in US study, but traditional risk factors and cocaine use main causes

US investigators have found a high prevalence of asymptomatic cardiovascular disease amongst HIV-positive patients. The study, involving an African-American population, found that 15% of patient had narrowing of the coronary arteries and is published in the February 15^th edition of Clinical Infectious Diseases.

But there was a high prevalence of traditional risk factors for heart disease in the study population, and many of the patients were also long-term cocaine users, a behaviour that has been associated with an increased risk of cardiovascular disease. The investigators were only able to attribute 1.6% of cases of asymptomatic heart disease to use of antiretroviral therapy.

Thanks to antiretroviral therapy many HIV-positive patients are living longer, healthier lives. However, anti-HIV drugs have been associated with metabolic complications. There is evidence that antiretroviral therapy can cause increases in blood lipids and sugars thereby elevating the longer-term risk of cardiovascular disease, and studies have also shown an increased incidence of cardiovascular events, such heart attack and stroke in antiretroviral-treated patients.

But few studies have looked at the relationship between the use of anti-HIV therapy and the risk of asymptomatic, or silent cardiovascular disease.

Nor have studies explored the connection between cocaine use, which is increased in some HIV-infected populations, and the risk of asymptomatic cardiovascular illness.

Investigators from Johns Hopkins University in Baltimore therefore undertook a study involving 165 HIV-positive African-American patients. None had diagnosed heart disease. These patients provided demographic information and had a CT examination of the heart to check for narrowing of the coronary arteries. Blood pressure was also measured and cholesterol levels were checked. Information was also obtained from patients about the duration and type of antiretroviral therapy (if any) and about their drug use behaviours.

The patients had a median age of 44 years, 36% were women and 24% had a family history of heart disease. Drug use levels were high with 90% being cocaine users, 35% for 15 years or more.

Overall, the prevalence of narrowing of the coronary artery revealed by the heart CT was 15%. Only 7% of antiretroviral-naïve patients had asymptomatic heart disease compared to 25% of patients who had taken six or more months of anti-HIV treatment (p = 0.03).

But the connection between antiretroviral therapy and asymptomatic heart disease was not so straightforward.

The investigators found that conventional risk factors for heart disease were strongly associated with asymptomatic narrowing of the coronary arteries. These included male sex (adjusted OR, 5.04; 95% CI, 1.19 – 31.5), high blood pressure (adjusted OR, 5.94; 95% CI, 1.58 – 25.5,), and high LDL cholesterol (adjusted OR, 6.10; 95% CI, 1.69 – 25.2).

Cocaine use for over 15 years was also an important risk factor (adjusted OR, 7.75; 95% CI, 2.26 – 31.2), but so too was over six months of antiretroviral therapy (adjusted OR, 4.35; 95% CI, 1.3 – 16.4).

The investigators then controlled for the traditional heart disease risk and cocaine use for 15 years or more and found that treatment with d4T (stavudine, Zerit for six months or more was associated with asymptomatic narrowing of the coronary artery (p = 0.02) as was six months or more of treatment with Combivir (p = 0.043).

But when the investigators calculated the proportion of asymptomatic heart disease caused by each of their significant risk factors they found that anti-HIV therapy for six months or more was responsible for just 1.6% of cases, the other cases being attributable to traditional risk factors or cocaine use.

The investigators conclude, “the study strongly suggests that, for HIV-infected patients receiving antiretroviral therapy, an aggressive reduction of traditional risk factors for cardiovascular disease, including the lowering of LDL cholesterol and maintaining optimal blood pressure, is ultimately vital to lower the risk of cardiovascular disease.” Regular exercise, and stopping smoking should be recommended to all HIV-positive patients, however “the most important intervention for HIV-infected persons receiving antiretroviral therapy is lifestyle modification, including cocaine use cessation.