Pre-therapy inflammation and coagulation activation and long-term CD4 count responses to the initiation of antiretroviral therapy

Abstract

Objectives: Pre-antiretroviral therapy (ART) inflammation and coagulation activation predict clinical outcomes in HIV-positive individuals. We assessed whether pre-ART inflammatory marker levels predicted the CD4 count response to ART.

Methods: Analyses were based on data from the Strategic Management of Antiretroviral Therapy (SMART) trial, an international trial evaluating continuous vs. interrupted ART, and the Flexible Initial Retrovirus Suppressive Therapies (FIRST) trial, evaluating three first-line ART regimens with at least two drug classes. For this analysis, participants had to be ART-naïve or off ART at randomization and (re)starting ART and have C-reactive protein (CRP), interleukin-6 (IL-6) and D-dimer measured pre-ART. Using random effects linear models, we assessed the association between each of the biomarker levels, categorized as quartiles, and change in CD4 count from ART initiation to 24 months post-ART. Analyses adjusted for CD4 count at ART initiation (baseline), study arm, follow-up time and other known confounders.

Results: Overall, 1084 individuals [659 from SMART (26% ART naïve) and 425 from FIRST] met the eligibility criteria, providing 8264 CD4 count measurements. Seventy-five per cent of individuals were male with the mean age of 42 years. The median (interquartile range) baseline CD4 counts were 416 (350-530) and 100 (22-300) cells/μL in SMART and FIRST, respectively. All of the biomarkers were inversely associated with baseline CD4 count in FIRST but not in SMART. In adjusted models, there was no clear relationship between changing biomarker levels and mean change in CD4 count post-ART (P for trend: CRP, P = 0.97; IL-6, P = 0.25; and D-dimer, P = 0.29).

Conclusions: Pre-ART inflammation and coagulation activation do not predict CD4 count response to ART and appear to influence the risk of clinical outcomes through other mechanisms than blunting long-term CD4 count gain.

Keywords: C-reactive protein; CD4 count; D-dimer; HIV; antiretroviral therapy; coagulation; highly active antiretroviral therapy; immunological response; inflammation; interleukin-6.

Fig. 1

Change in CD4 count since (re)initiation of antiretroviral therapy (ART) by pre-ART quartiles of biomarkers. (a) Interleukin-6 (IL-6) and CD4 count change. (b) C-reactive protein (CRP) and CD4 count change. (c) D-dimer and CD4 count change. (d) Inflammation rank score (see main text for details) and CD4 count change. Q, quartile (Q1, first quartile etc.); SMART, Strategic Management of Antiretroviral Therapy trial; FIRST, Flexible Initial Retrovirus Suppressive Therapies trial.