CD4+ count and viral load were complementary and were independently associated with increased incidence of AF.
With the advent of highly active antiretroviral therapy, HIV infection has evolved from a terminal illness into a chronic disease. Because individuals live longer with HIV infection, we are seeing associations between HIV infection and cardiovascular diseases.
Compared with the signature atherosclerotic plaques of coronary disease from hyperlipidemia, HIV-associated coronary artery disease usually presents as diffuse coronary artery narrowing and is thought to have a distinct pathophysiology, driven primarily by a hyperinflammatory state. Although cardiac arrhythmias, such as atrial fibrillation (AF), share risk factors with atherosclerosis and can have an inflammatory basis, this association to date has never been analyzed in HIV-infected individuals.
In a recent study, published in the Journal of the American College of Cardiology, Hsu et al1 reported that markers of HIV severity (CD4+ count and viral load) were complementary and were independently associated with increased incidence of AF. In a Veterans Affairs cohort of 30,533 HIV-infected individuals with no known history of AF, followed over a median of 6.8 years, the incidence of AF was 2.6%, a rate higher than what would be expected in a similar non–HIV-infected population. Using time-updated multivariable adjustment for other factors traditionally associated with AF (age, gender, race, comorbidities, body mass index, glomerular filtration rate, proteinuria), the authors were able to demonstrate that patients with a lower CD4+ count and a higher viral load had increased incident AF. A CD4+ count of less than 200/μL was associated with a 1.4 times higher risk (P = .018) and a viral load greater than 100,000/μL was associated with a 1.7 times higher risk (P = .002). This association remained significant even after adjusting for the higher number of health care visits associated with more severe HIV infection.
Although the biologic mechanism of this association is yet to be defined, this study is groundbreaking in that it is the first to establish this relationship. Additional data are certainly needed, but the association suggests that better HIV control may decrease incident AF in this vulnerable population.
1. Hsu JC, Li Y, Marcus GM, et al. Atrial fibrillation and atrial flutter in HIV-infected persons: incidence, risk factors, and association wtih markers of HIV disease severity. J Am Coll Cardiol. 2013 Apr 3; doi:10.1016/j.jacc.2013.03.022; [Epub ahead of print].