Objective: HIV-infected individuals are at high risk of developing cardiovascular disease. Whether earlier initiation of HIV therapy at higher CD4 cell counts has any effect on cardiovascular risk as assessed by endothelial function is unknown.
Design: Cross-sectional study of 74 antiretroviral-treated men with undetectable plasma HIV RNA levels.
Methods: Participants underwent noninvasive assessment of endothelial function using brachial artery flow-mediated dilation (FMD). The association of nadir and current CD4 T-cell count with FMD was assessed using multivariable linear regression.
Results: The median age was 47 years [interquartile range (IQR) 42-55], median current CD4 T-cell count was 659 cells/μl (IQR 542-845), and nadir CD4 cell count was 314 cells/μl (IQR 150-490). Twenty-eight percent had hypertension, and 32% hyperlipidemia. Nadir CD4 T-cell count less than 350 cells/μl was associated with lower FMD in age-adjusted and race-adjusted analyses and remained an independent predictor of FMD after adjustment for cardiovascular risk factors (hypertension, diabetes, smoking, hyperlipidemia) and HIV-related characteristics (HIV duration, HAART duration). After multivariable adjustment, individuals with nadir CD4 T-cell count less than 350 cells/μl had a 1.22% lower FMD compared with those with higher T-cell counts [95% confidence interval (CI) -2.20 to -0.19, P=0.02]. Proximal CD4 T-cell count showed little association with FMD.
Conclusion: Among treated HIV-infected individuals, nadir CD4 T-cell count less than 350 cells/μl is independently associated with lower FMD, suggesting that delayed therapy results in sustained harm to endothelial function. Our data support future prospective studies evaluating cardiovascular effects of HAART initiation at higher CD4 cell counts.