Background: Previous research has demonstrated an increase in carotid intima-media thickness (cIMT) in HIV-infected individuals compared to controls. However, the reason for this increased level of subclinical vascular disease is unknown.
Objective: To identify HIV-related risk factors for increased cIMT.
Methods: We evaluated the relationship between HIV-related characteristics (including markers of HIV disease severity and use of antiretroviral therapy) and cIMT measurements in the internal/bulb and common carotid regions among 538 HIV-infected participants from the Study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM). We used Bayesian model averaging to estimate the posterior probability of candidate HIV and non-HIV-related risk factors being true predictors of increased cIMT. Variables with a posterior probability of more than 50% were used to develop a selected regression model for each of the anatomic regions.
Results: For common cIMT, the Bayesian model selection process identified age, African-American race, and systolic and diastolic blood pressure with probability more than 95%, HDL cholesterol with probability 85% and Hispanic ethnicity with probability 51%. Among the HIV-related factors included in the analysis, only tenofovir use was selected (51% probability). In the selected model, duration of tenofovir use was associated with lower common cIMT (-0.0094 mm/year of use; 95% confidence interval: -0.0177 to -0.0010). For internal cIMT, no HIV-related risk factors were above the 50% posterior probability threshold.
Conclusion: We observed an inverse association between duration of tenofovir use and common carotid cIMT. Whether this association is causal or due to confounding by indication needs further investigation.
Trial registration: ClinicalTrials.gov NCT00331448.