Initiation of antiretroviral therapy at higher nadir CD4+ T-cell counts is associated with reduced arterial stiffness in HIV-infected individuals

Abstract

Objective: HIV infection is associated with increased rates of cardiovascular disease. We sought to evaluate whether initiation of HIV therapy at higher nadir CD4⁺ T-cell counts might reduce cardiovascular risk, as measured by arterial stiffness. Design: We conducted a cross-sectional study of 80 HIV-infected men who were antiretroviral-treated with undetectable plasma HIV RNA levels. Methods: Participants underwent noninvasive assessment of arterial stiffness by pulse wave analysis (augmentation index normalized for heart rate of 75 bpm) and carotid–femoral pulse wave velocity, both sensitive measures of cardiovascular risk. A generalized linear model was used to determine the relationship between cardiovascular and HIV-related predictors, and arterial stiffness. Results: In unadjusted analyses, predictors of arterial stiffness included age, blood pressure, antihypertensive medication use, and nadir CD4⁺ T-cell count below 350 cells/μl (all P < 0.05). After adjusting for both cardiovascular risk factors (age, blood pressure, antihypertensive medication use, diabetes, hypercholesterolemia, and smoking) and HIV-related covariates, nadir CD4⁺ T-cell count below 350 cells/μl was independently associated with a 0.41 m/s increase in pulse wave velocity (95% confidence interval 0.03–0.79, P = 0.03) and a 7.3% increase in augmentation index (augmentation index normalized for heart rate of 75 bpm; 95% confidence interval 2.6–11.9, P = 0.003). Neither duration of antiretroviral therapy nor exposure to protease inhibitors was associated with arterial stiffness. Conclusion: Among treated HIV-infected individuals, arterial stiffness is independently associated with both traditional cardiovascular risk factors as well as a low nadir CD4⁺ T-cell count. Our data suggest that cardiovascular risk among HIV-infected individuals could be reduced through early initiation of antiretroviral therapy, before CD4⁺ T-cell counts are depressed, a concept that should be tested prospectively in future studies.