Abstract 5096: Early versus Late Initiation of Antiretroviral Therapy and Arterial Stiffness in HIV Infection

Abstract

Background: HIV infection is associated with increased rates of cardiovascular disease. Assessment of arterial stiffness via pulse wave velocity (PWV) is strongly associated with cardiovascular risk, and prior studies have shown that HIV-infected patients have higher stiffness compared to controls. Current guidelines recommend initiation of antiretroviral therapy at a CD4 T cell count of 350 cells/ul. Whether earlier initiation of HIV therapy has any effect on cardiovascular risk as assessed by PWV is unknown. Methods: We conducted a cross-sectional study of 81 HIV-infected men who were antiretroviral-treated with undetectable plasma HIV RNA levels. Subjects underwent noninvasive assessment of PWV using the SphygmoCor System (AtCor Medical, Australia). A generalized linear model was used to determine the relationship between traditional cardiovascular risk factors, HIV-related predictors, and arterial stiffness as measured by PWV. Results: The median age was 47 years (IQR 43–54), 36% had a history of hypertension, and 46% had hypercholesterolemia. The median current CD4 T cell count was 539 cells/ul (IQR 324 –736), and nadir CD4 count was 180 cells/ul (IQR 29 –311). The median PWV was 5.3 m/s (IQR 4.9 – 6.2). In unadjusted analyses, age, diabetes, current CD4 count and nadir CD4 count <350 were predictors of PWV (all p <0.05). After adjusting for both traditional cardiovascular risk factors (age, systolic and diastolic BP, hypertension, diabetes, hypercholesterolemia, smoking) and HIV-related covariates, a nadir CD4 count <350 remained independently associated with a 0.58 m/s increase in PWV (95% CI 0.15–1.01, p<0.008). Other significant determinants of PWV in multivariate analyses included age, systolic and diastolic BP, and diabetes. Of note, neither duration of antiretroviral therapy nor exposure to protease inhibitors was associated with degree of arterial stiffness. Conclusions: Among treated HIV-infected individuals, higher PWV is independently associated with both traditional cardiovascular risk factors including age and diabetes, as well as low nadir CD4 count. Our data support the concept that initiation of antiretroviral therapy before low CD4 counts occur may reduce cardiovascular risk among individuals with HIV infection.