Risk of Heart Disease among HIV-Positive Veterans

Due to the success of treatment with antiretroviral therapy (ART), people with HIV live longer, but are at risk for heart disease, according to researchers. Previous studies have found an association between HIV and acute myocardial infarction (AMI); however, “the results may have been confounded by the choice of reference group, the lack of adjudicated AMI outcomes, a lack of fatal events, and/or missing risk factor data,” the researchers said.

To investigate whether HIV is associated with an increased risk of AMI after adjustment for all standard Framingham risk factors, the researchers compared a large cohort of HIV-positive veterans with demographically and behaviorally similar (similar prevalence of smoking and use of alcohol and cocaine) uninfected veterans. They reported results of their investigation in JAMA Internal Medicine [2013;173(8):614-622].

The study cohort included participants in the Veterans Aging Cohort Study Virtual Cohort (VACS-VC) from April 1, 2003, through December 31, 2009. The main outcome measure was AMI. Baseline was a participant’s first clinical encounter on or after April 1, 2003. Follow-up was from the baseline date to an AMI event, death, or last follow-up date (12/31/2009).

After excluding participants with baseline cardiovascular disease, the researchers analyzed data on 82,459 participants. Although VACS-VC HIV-positive and uninfected veterans were matched for race and age at enrollment, there were some differences by HIV status. The prevalence of Framingham risk factors differed by HIV status (P≤.001 for all). Current smoking, low high-density lipoprotein cholesterol, and elevated triglycerides were more common among HIV-positive participants. For both HIV-positive and uninfected participants, the median coronary heart disease (CHD) risk was Framingham Risk Score 6 (intermediate risk) at baseline.

Median follow-up was 5.9 years. There were 871 AMI events (41.7%) among HIV-positive participants. Of the 871 events, 61.3% (n=534) were within or transferred to the VA (Quality Enhancement Research Initiative), 18.5% (n=161) were outside the VA and never transferred to VA facilities (Medicare events), and 20.5% (n=176) were deaths.

The AMI rates per 1000 person-years were significantly higher among the HIV-positive cohort, compared with the uninfected cohort. For those 40 to 49 years of age, the rates were 2.0 (95% confidence interval [CI], 1.6-2.4) versus 1.5 (95% CI, 1.3-1.7), respectively. The rates for those 50 to 59 years of age were 3.9 (95% CI, 3.3-4.5) versus 2.2 (95% CI, 1.9-2.5), respectively. For participants 60 to 69 years of age, the rates were 5.0 (95% CI, 3.80-6.7) in the HIV-positive cohort versus 3.3 (95% CI, 2.6-42) for participants in the uninfected cohort (P<.05 for all comparisons).

The increased risk of incident AMI among the HIV-positive cohort compared with the uninfected cohort remained after adjusting for Framingham risk factors, comorbidities, and substance use (hazard ratio [HR], 1.48; 95% CI, 1.27-1.72). An excess risk remained among those achieving an HIV-1 RNA level <500 copies/mL, compared with uninfected veterans in time-updated analyses (HR, 1.39; 95% CI, 1.17-1.66).

“Infection with HIV is associated with a 50% increased risk of AMI beyond that explained by recognized risk factors,” the researchers said. “Future studies should focus on validating the Framingham Risk Score in cohorts with HIV-positive people using hard CHD end points and assessing whether the inclusion of HIV status and race/ethnicity comorbidites, HIV-specific biomarkers and ART, and/or inflammatory biomarkers improves CHD risk prediction for HIV-positive people.”