Assessment of arterial elasticity among HIV-positive participants with high CD4 cell counts: a substudy of the INSIGHT Strategic Timing of AntiRetroviral Treatment (START) trial.

OBJECTIVES: Both HIV infection and antiretroviral therapy (ART) may increase cardiovascular disease (CVD) risk. Assessments of vascular function and structure can be used to study the pathogenesis and progression of CVD, including the effects of ART and other interventions. The objective of this report is to understand methods to assess vascular (dys)function and report our experience in the Arterial Elasticity Substudy in the Strategic Timing of AntiRetroviral Treatment (START) trial. METHODS: We review literature and analyze baseline data from the Arterial Elasticity Substudy, which estimated vascular (dys)function through analysis of the diastolic blood pressure (BP) waveform. Linear regression was used to study cross-sectional associations between baseline clinical factors and small or large arterial elasticity. RESULTS: Arterial elasticity measurement was chosen for its improved measurement reproducibility over other methodologies and the potential of small arterial elasticity to predict clinical risk. Analysis of baseline data demonstrates that small artery elasticity is impaired (lower) with older age and differs by race and between geographical regions. No HIV-specific factors studied remained significantly associated with arterial elasticity in multivariate models. CONCLUSIONS: Longitudinal analyses in this substudy will provide essential randomized data with which to study the effects of early ART initiation on the progression of vascular disease among a diverse global population. When combined with future biomarker analyses and clinical outcomes in START, these findings will expand our understanding of the pathogenesis of HIV-related CVD.

Determinants of incident chronic kidney disease and progression in a cohort of HIV-infected persons with unrestricted access to health care.

OBJECTIVES: As socioeconomic factors may impact the risk of chronic kidney disease (CKD), we evaluated the incidence and risk factors of incident CKD among an HIV-infected cohort with universal access to health care and minimal injecting drug use (IDU). METHODS: Incident CKD was defined as an estimated glomerular filteration rate (eGFR) <60 ml/min/1.73 m(2) for ≥ 90 days. eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Rates were calculated per 1000 person-years (PY). Associations with outcomes were assessed using two separate Cox proportional hazard models, adjusting for baseline and time-updated covariates. RESULTS: Among 3360 participants [median age 29 years; 92% male; 44% African American (AA)] contributing 23,091 PY of follow-up, 116 developed incident CKD [5.0/1000 PY; 95% confidence interval (CI) 4.2-6.0/1000 PY]. The median first eGFR value was 97.0 mL/min/1.73 m(2) [interquartile range (IQR) 85.3-110.1 mL/min/1.73 m(2)]. Baseline factors associated with CKD included older age, lower CD4 count at HIV diagnosis [compared with CD4 count ≥ 500 cells/µL, hazard ratio (HR) 2.1 (95% CI 1.2-3.8) for CD4 count 350-499 cells/µL; HR 3.6 (95% CI 2.0-6.3) for CD4 count 201-349 cells/µL; HR 4.3 (95% CI 2.0-9.4) for CD4 count ≤ 200 cells/µL], and HIV diagnosis in the pre-highly active antiretroviral therapy (HAART) era. In the time-updated model, low nadir CD4 counts, diabetes, hepatitis B, hypertension and less HAART use were also associated with CKD. AA ethnicity was not associated with incident CKD in either model. CONCLUSIONS: The low incidence of CKD and the lack of association with ethnicity observed in this study may in part be attributable to unique features of our cohort such as younger age, early HIV diagnosis, minimal IDU, and unrestricted access to care. Lower baseline CD4 counts were significantly associated with incident CKD, suggesting early HIV diagnosis and timely introduction of HAART may reduce the burden of CKD.

A randomized comparison of two instruments for measuring self-reported antiretroviral adherence.

A randomised trial compared two instruments for assessing self-reported adherence to antiretroviral medications: (1) a day-by-day recall instrument that elicited the number of missed doses in each of the prior three days (3-day instrument; n=64) and (2) a general recall instrument that elicited an estimate of proportion of pills taken during the prior seven days (7-day instrument; n=70). Adherence was measured at study visits over 12 months among participants in a clinical trial assessing treatment strategies for individuals with virologic failure and multidrug-resistant HIV. Participants had a median (interquartile range) of 133 (41-264) CD4 cells/ml(3) and a median of 10 major HIV resistance mutations at baseline. Mean adherence levels were 90-98% throughout the study. There was a greater trend in the likelihood of 100% adherence when measured by the 3-day versus the 7-day instrument (odds ratio (OR)=1.45; p=0.06). The likelihood of consistent 100% adherence measured by either instrument decreased over time (p<0.001). Participants reporting 100% adherence at more than half of study visits had better virologic and immunologic outcomes at month-12 compared to those reporting 100% adherence at half or fewer visits (HIV RNA decline of 0.96 versus 0.51 log, respectively, p=0.02; and CD4 cell increase of 51.0 versus 17.8 cells, p=0.04). This study demonstrated the utility of the general 7-day recall adherence self-report instrument as well as the 3-day day-by-day recall adherence self-report instrument for measuring antiretroviral adherence. Self-reported adherence was significantly associated with virologic and immunologic outcomes in this population with advanced drug-resistant HIV disease.