Effects of national adoption of Treat-All guidelines on pre-ART CD4 testing and viral load monitoring after ART initiation: A regression discontinuity analysis.

BACKGROUND The World Health Organization's Treat-All guidance recommends CD4 testing prior to antiretroviral treatment (ART) initiation, and routine viral load (VL) monitoring (over CD4 monitoring) for patients on ART. METHODS We used regression discontinuity analyses to estimate changes in CD4 testing and VL monitoring among 547,837 ART-naive patients enrolling in HIV care during 2006-2018 at 225 clinics in 26 countries where Treat-All policies were adopted. We examined CD4 testing within 12 months before and VL monitoring 6 months after ART initiation among adults (≥20 years), adolescents (10-19 years) and children (0-9 years) in low/lower-middle income countries (L/LMICs) and high/upper-middle income countries (H/UMICs). RESULTS Treat-All adoption led to an immediate decrease in pre-ART CD4 testing among adults in L/LMICs, from 57.0% to 48.1% (-8.9 percentage points [pp]; 95% CI: -11.0, -6.8), and a small increase in in H/UMICs, from 90.1 to 91.7% (+1.6pp; 95% CI: 0.2, 3.0), with no changes among adolescents or children; decreases in pre-ART CD4 testing accelerated after Treat-All adoption in L/LMICs. In L/LMICs, VL monitoring after ART initiation was low among all patients just before Treat-All; while there was no immediate change at Treat-All adoption, VL monitoring trends significantly increased afterwards. In H/UMICs, VL monitoring increased among adults immediately after Treat-All adoption, from 58.2% to 61.1% (+2.9pp; 95% CI: 0.5, 5.4), with no significant changes among adolescents/children. CONCLUSIONS While on-ART VL monitoring has improved in L/LMICs, Treat-All adoption has accelerated and disparately worsened suboptimal pre-ART CD4 monitoring, which may compromise care outcomes for individuals with advanced HIV.