Findings of large study suggest that HIV should be considered a major risk factor for cardiovascular disease

People living with HIV are twice as likely to develop cardiovascular disease (CVD), according to the findings of a meta-analysis published in Circulation. The research also showed that HIV is the cause of 1% of global CVD cases and that the burden of HIV-associated CVD has tripled over the last 20 years. The majority of HIV-associated CVD was in sub-Saharan Africa and Asia Pacific.  

“The crude rate of incident cardiovascular disease was 60 per 10,000 person years and is comparable to other high-risk cardiovascular groups,” write the authors. “Our estimates have important policy implications for implementing appropriate cardiovascular risk stratification and treatment strategies across healthcare systems, especially in those countries with the greatest burden where resources remain limited.”

The study is warmly praised in an accompanying editorial that suggests that HIV should now be considered to be a major risk factor for CVD alongside diabetes mellitus, hypertension, elevated cholesterol and smoking.

Thanks to antiretroviral therapy, many people with HIV now have an excellent life expectancy. Non-HIV-related diseases, especially CVD, are now the principal cause of serious illness and death in HIV-positive individuals. The highest HIV-prevalence rates are in sub-Saharan Africa, a region that has also seen a steady increase in the burden of CVD over the past two decades. Recent research has identified plausible biological mechanisms for a direct link between HIV and CVD, including vascular inflammation, dyslipidaemia and insulin resistance.

Investigators wanted to establish a better understanding of the risk of CVD for people with HIV and the burden of CVD in this population.

They therefore conducted a systematic review and meta-analysis of all peer-reviewed longitudinal studies published until 2015 that examined these questions:

• Do people with HIV have an increased risk of CVD?
• What proportion of CVD risk can be attributed directly to HIV?
• What is the burden of HIV-related CVD?

Results were provided globally, regionally and nationally.

A total of 80 studies conducted between 1990 and 2015 met the inclusion criteria. When combined, they provided data on just under 800,000 people living with HIV and 3.5 million person-years.

The incidence of CVD among HIV-positive people was 61.8 per 10,000 person-years. The CVD mortality rate in HIV-positive people was 14.1 per 10,000 person-years (meaning that in a group of 10,000 people with HIV, 14 die of CVD each year).

Compared to HIV-negative individuals, the risk of CVD was over twofold higher for people with HIV (RR = 2.16; 95% CI, 1.68-2.77).

The proportion of CVD cases attributable to HIV (population-attributable fraction, or PAF) increased from 0.36% in 1900 to 0.92% in 2015.

This was associated with a significant worsening of the global CVD burden in HIV-positive people. The number of disability-adjusted life-years (DALYS) increased threefold from 0.74 million in 1990 to 2.57 million in 2015.

There were marked regional variations in the burden of CVD attributable to HIV. In 2015, East and Southern Africa, Asia and the Pacific, and West and Central Africa account for over two-thirds of global HIV-related CVD. The largest increase over the 26 years of the study was observed in East and Southern Africa.

National estimates showed that HIV accounted for at least 15% of CVD cases in Swaziland, Botswana, Lesotho and South Africa. HIV-associated CVD DALYs in sub-Saharan Africa increased from 0.21 million in 1990 to 0.74 million in 2015.

“The combined burden of HIV and cardiovascular disease in the UNAIDS high-priority countries is of growing concern and has important implications with respect to regional health policies, guidelines, and resource allocation,” comment the researchers. “Risk stratification and identification of patients at intermediate or high risk of future cardiovascular disease are already challenging in resource-limited nations. Furthermore, traditional risk scores perform poorly because they consistently underestimate risk in HIV-infected populations.”

The accompanying editorial praises the study for its “vast scope.” Its authors acknowledge that HIV physicians and cardiologists alike face challenges determining the mechanisms behind HIV-associated CVD and accurately predicting which people are at highest risk. Nevertheless, they conclude that the time has now come for HIV to be considered a major risk factor for CVD. This would both stimulate research and improve clinicians' awareness of the issue – potentially improving the prevention, detection and treatment of CVD in people living with HIV.