START substudies: increased quality of life from earlier treatment but no impact on vascular function or cardiovascular markers

Gareth Hardy, HIV i-Base

A number of sub-studies from the START trial were presented at CROI 2016 that continue to show results that were not widely predicted.

START has already showed effects of initiating ART immediately versus deferring (when CD4 count falls to 350) on various non-AIDS associated morbidities.

The first sub-study – on quality of life (QoL) – was presented by Alan Lifson from University of Minnesota. [1]

QoL assessments consisted of three different tests: a visual analogue scale (VAS) for self-assessment of overall current health and then three measures of quality of life based on results from the Short-Form 12-Item Health Survey version 2 (SF-12v2): General health perception (GHP); physical component summary (PCS), and mental component summary (MCS).

Data was collected from 4561 START study participants, who had a median baseline CD4 count of 651 cells, median age 36 years, and 27% of which were female, with 46% from high-income countries.

All quality of life measures improved for the immediate treatment group versus the deferred treatment group, from month 4 to 12 (all p<0.001). Differences between the treatment groups during follow-up were estimated as: VAS=1.9 (95% CI 1.2-2.5); GHP=3.6 (2.8-4.5); PCS=0.8 (0.5-1.1); MCS=0.9 (0.4-1.3). Although these differences were significant, they were also modest. It was noted that improvements in physical and mental health assessments occurred in equal measure.

A second sub-study looked at artery elasticity in 332 START participants, randomised to either immediate ART or deferred ART. The investigators assessed diastolic blood pressure waveform contour, which they have previously shown is altered in HIV positive people who are not on ART and also in those with advancing age. [2]

The median age of sub-study participants was 33 years, 70% of participants were male. Cardiovascular risk factors were considered to be low in this cohort at study entry.

No differences were found in small or large arterial elasticity between or within either group during the study. Dr Baker noted that the follow up duration remains modest for assessment of potentially cumulative effects of ART toxicity, when considering the time frame for development of CVD.

Finally, also presented by Jason Baker in a poster, a third sub-study looking at differences in cardiovascular factors between the immediate vs deferred ART groups. [3]

The baseline characteristics of participants in this sub-study were similar to those in the vascular function sub-study described above.

All lipid parameters (total cholesterol, low-density lipoprotein [LDL]-cholesterol, high-density lipoprotein [HDL]-cholesterol, total cholesterol to HDL-C ratio) and fasting glucose increased significantly in the immediate treatment group compared to the deferred treatment group (all p <0.001). Incident dyslipidaemia was also greater among the immediate versus deferred treatment group (HR 1.62, [95% CI: 1.33-1.94]). There were no changes in incident diabetes or hypertension between the groups.

Although immediate ART was associated with increases in LDL-C and dyslipidaemia, concurrent increases in HDL-C and other mixed effects meant that there was no consistent difference in CVD risk scores between the groups over time.

References:

Lifson A et al. Increased quality of life with immediate ART initiation: results from the START trial. 23rd CROI, 22-25 February 2016, Boston.
http://www.croiconference.org/sessions/increased-quality-life-immediate-art-initiation-results-start-trial (abstract)
http://www.croiconference.org/sites/default/files/posters-2016/475.pdf (PDF poster)
Baker JV et al. Early antiretroviral therapy does not improve vascular function: A START substudy. 23rd CROI, 22-25 February 2016, Boston. Poster abstract 475.
Baker JV et al. Changes in CVD risk factors with early and deferred ART in the START Trial. 23rd CROI, 22-25 February 2016, Boston.
http://www.croiconference.org/sessions/changes-cvd-risk-factors-early-and-deferred-art-start-trial (abstract)
http://www.croiwebcasts.org/console/player/29442 (webcast)