Risk of Sudden Cardiac Death Higher Among HIV Subgroup

CD4 counts below 200 cells/mm³ or an HIV viral load above 500 copies/mL were linked to a greater risk of sudden cardiac death (SCD) among veterans participating in the Veterans Aging Cohort Study (VACS), according to a new study published in Journal of the American Heart Association.

The observational, longitudinal cohort study found 57% (HR, 1.57; 95% CI, 1.28-1.92) and 70% (HR, 1.70; 95% CI, 1.46-1.98) higher risks of SCD among veterans living with HIV who had low CD4 counts and high viral loads, respectively, vs those without HIV. Even adjusting for potential confounders still resulted in an overall 14% (HR, 1.14; 95% CI, 1.04-1.25) higher risk of SCD.

“People living with HIV have an excess risk of cardiovascular disease from factors that include chronic immune activation and inflammation, antiretroviral therapy–related dyslipidemia, and behaviors such as smoking and alcohol consumption,” the authors wrote. “Whether HIV infection is an independent risk factor for SCD, however, is unclear because data are sparse.”

Their study objective was to examine this potential association, with SCD defined by a combination of criteria from the World Health Organization and comprehensive chart review.

The participants, matched 1:2 (n = 43,407 with HIV; n = 100,929 without HIV), were enrolled in VACS on or after April 1, 2003, and followed until the first of these 3 points: first SCD, first other death, or December 31, 2014. Most participants were men, of Black or White ethnicity, had low-density lipoprotein cholesterol levels below 100 mg/dL or from 100 to 129 mg/dL, had triglyceride levels of at least 150 mg/DL, were current smokers, did not have comorbid hepatitis C infection, and had normal kidney function.

SCD incidence rates were stratified by HIV status, baseline HIV viral load/CD4 count, and decade age group.

There were 3035 SCDs throughout the study period, with 26% occurring among the veterans living with HIV. Unadjusted rates per 100,000 person-years were close to equal (232 among those with HIV vs 234 among those without HIV), and SCD totals increased per age decade per 100,000 person-years in both groups.

The differentiating factor was that in addition to older age, lower baseline CD4 counts and higher HIV viral load increased the SCD risk in the HIV cohort alone. Stratifying by HIV status, CD4 count, and viral load produced these results, per 100,000 person-years:

• 259 SCDs occurred among those living with HIV and CD4 counts below 200 cells/mm³ vs 222 among those with HIV and CD4 counts at least 500 cells/mm³.
• 238 SCDs occurred among those living with HIV and a viral load of at least 500 copies/mL vs 220 among those with HIV below 500 copies/mL.
• CD4 and viral load data were missing on 245 and 243 persons, respectively, living with HIV.

For those living with HIV who had a CD4 count above 500 cells/mm³ and a viral load below 500 copies/mL, SCD risk did not increase.

Risk of SCD was also higher if a study participant was a minority ethnicity and living with HIV (HR, 1.73; 95% CI, 1.16-2.59) or did not have HIV but had diabetes (HR, 1.44; 95% CI, 1.30-1.59).

“These findings have important implications for people living with HIV and people without HIV and their providers,” the authors wrote, highlighting that their data on viral load suppression and preventing/managing SCD risk factors could help clinicians target non-AIDS diseases.

“Our data suggest that treating HIV infection and the associated risk factors for SCD could reduce SCD risk among people living with HIV,” they concluded. “Future studies should examine the underlying mechanisms for SCD among people living with HIV.”

Reference

Freiberg MS, Duncan MS, Alcorn C, et al. HIV infection and the risk of World Health Organization–defined sudden cardiac death. J Am Heart Assoc. Published online September 8, 2021. doi:10.1161/JAHA.121.021268