Abstract
INTRODUCTION: The Thai National AIDS programme (NAP) treatment guidelines have recommended rapid antiretroviral therapy (ART) initiation, regardless of CD4 count since 2014. We assessed treatment outcomes among youth living with HIV (YLHIV), initiating first-line ART and assessed the association between virological failure (VF) and timing of ART initiation. METHODS: We retrospectively reviewed data for YLHIV aged 15-24 years, initiating non-nucleoside reverse transcriptase inhibitor-based ART from 2014 to 2019, through the NAP database. We classified the timing of ART into three groups based on duration from HIV-positive diagnosis or system registration to ART initiation: (1) <1 month (rapid ART); (2) 1-3 months (intermediate ART); and (3) >3 months (delayed ART). VF was defined as viral load (VL) ≥ 1000 copies/ml after at least 6 months of first-line ART. Factors associated with VF were analysed using generalized estimating equations. RESULTS: Of 19,825 YLHIV who started ART, 78% were male. Median (interquartile range, IQR) age was 21 (20-23) years and CD4 count was 338 (187-498) cells/mm(3) . After registration, 12,216 (62%) started rapid ART, 4272 (22%) intermediate ART and 3337 (17%) delayed ART. The proportion of YLHIV starting ART <30 days significantly increased from 43% to 57% from 2014-2016 to 2017-2019 (p < 0.001). The median duration of first-line therapy was 2 (IQR 1-3) years and 89% started with efavirenz-based regimens. Attrition outcomes showed that 325 (2%) died (0.73 [95% CI 0.65-0.81] per 100 person-years [PY]) and 1762 (9%) were loss to follow-up (3.96 [95% CI 3.78-4.15] per 100 PY). Of 17,512 (88%) who had VL checked from 6 to 12 months after starting treatment, 80% achieved VL <200 copies/ml. Overall, 2512 experienced VF 5.87 (95% CI 5.65-6.11) per 100 PY). In a multivariate model, the adjusted incidence rate ratio for VF was 1.47 (95% CI 1.33-1.63, p < 0.001) in the delayed ART group and 1.14 (95% CI 1.03-1.25, p< 0.001) in the intermediate ART group, compared to YLHIV in the rapid ART group. CONCLUSIONS: Rapid ART initiation after diagnosis was associated with significantly reduced risks of VF and death in YLHIV, supporting the implementation of rapid ART for optimizing health outcomes.