Heart Attack Prediction Methods Leave HIV Population At-Risk
Current tools to predict the risk of heart attack and stroke vastly underestimate the risk in individuals with HIV, which is nearly double that of the general population, reports a new Northwestern Medicine study. The higher risk for heart attack — about 1.5 to two times greater — exists even when the virus itself is undetectable due to antiretroviral drugs.
“The actual risk of heart attack for people with HIV was roughly 50 percent higher than predicted by the risk calculator many physicians use for the general population,” said Matthew Feinstein, MD, a cardiovascular disease fellow at Northwestern University Feinberg School of Medicine.
Accurately predicting an individual’s risk helps determine whether he or she should take medications such as statins to reduce the risk of heart attack or stroke.
“If you have a higher risk for heart attack or stroke, your ability to benefit from one of these drugs is greater and justifies the possible side effects of a medication,” Feinstein said. A new predictive algorithm may need to be developed to determine the actual risk for heart attack and stroke in people with HIV, he noted.
An estimated 1.2 million people in the United States are HIV-positive with 35 million to 40 million living with HIV worldwide. Scientists analyzed data from approximately 20,000 HIV-positive individuals who received care at one of five participating sites. They compared predicted rates of heart attacks based on data from the general population to the actual rates of heart attacks observed in this group of participants. The scientists believe HIV to be the primary driver of the higher risk of heart attack.
HIV lurks in the body’s tissues – even in people whose blood tests don’t show any sign of the virus in the blood – and creates chronic inflammation, which in turn causes plaque buildup that can lead to heart attack or stroke. Plaque buildup occurs 10 to 15 years earlier in HIV patients than in the general population.
“It’s this inflammatory state that seems to drive the accelerated aging and higher risks for heart disease, which are becoming more common in HIV patients as they live longer,” Feinstein said.
In addition to inflammation and other effects from the virus as factors in higher heart attack and stroke rates, the scientists also pointed to higher rates of traditional risk factors like smoking. While not ideal, the scientists still consider risk scores developed for the general population to be useful in assessing risk for people with HIV.
Feinstein and colleagues hope to collaborate on an even larger multi-center HIV study to develop a new algorithm to determine risk. While the most recent study included 20,000 participants, the current tool for predicting heart attack risk for the general population is based on more than 200,000 patients.
“Regardless of age, sex or race, the risks are higher in people with HIV,” Feinstein said. Of HIV-positive groups, the study found the current predictor tool was least accurate in African American men and women and most effective for Caucasian men.
The study builds on previous HIV-related heart disease research by Feinstein that found individuals with HIV had more scarring in the heart muscle after heart attacks, indicating an impaired ability to heal. The reasons for this are an area of active study for Feinstein and his colleagues.
A clinical trial is underway at Northwestern Medicine to evaluate how well common medications for heart disease prevention and treatment, such as statin medications, work to prevent heart disease in the HIV-positive population.