Age-specific all-cause mortality rates among adolescents and youth living with and without HIV: Evidence from a cohort study in South Africa.

INTRODUCTION: Mortality among adolescents living with HIV (ALHIV) remains a global health problem. We lack granular (age- and sex-disaggregated) data on mortality among ALHIV, hence, this study aims to assess all-cause mortality among ALHIV in a low-resource setting. METHODS: All adolescents ever initiated on antiretroviral treatment (ART, N = 1107) and their HIV-negative peers (N = 456) aged 10-19 years, recruited as part of the Mzantsi Wakho study cohort, were followed up between 2014 and 2022 (yielding 12,427.7 person-years of follow-up). First, we assessed the proportion of deaths and estimated crude mortality incidence rates per 100 person-years of follow-up and their 95% confidence intervals, stratified by HIV status, sex and mode of HIV acquisition (vertical vs. sexual). We then estimated adjusted incidence rate ratios (IRRs) using Poisson regression adjusted for time-varying age, sex and time on ART. Last, we used the Cox proportional hazards regression model to estimate the risk of death by ART adherence. RESULTS: A total of 1563 adolescents and young people were included in this analysis, 70.8% ALHIV and 57% female. More deaths occurred in ALHIV compared to their HIV-negative peers (8.3% vs. 0.4%, p<0.001). Among ALHIV, we observed a significantly higher proportion of deaths among males compared to females (10.7% vs. 7.1%, p = 0.036). Overall, mortality increased significantly with age, and males had a higher risk of mortality compared to females. Adolescents and youth living with vertically acquired HIV had a higher risk of mortality than those living with sexually acquired HIV. Comparing mortality rates by mode of HIV acquisition stratified by age and sex, mortality risk was higher among females aged 20+ years with vertically acquired HIV (IRR: 3.61, 95% CI 1.48-8.82) compared to females with sexually acquired HIV of the same age group. In a sub-sample analysis, sustained ART adherence was associated with a lower risk of death (aHR: 0.44, 95% CI 0.23-0.85). CONCLUSIONS: ALHIV experience higher all-cause mortality than their HIV-negative peers, despite having initiated ART. Among ALHIV, mortality risk was higher among males and adolescents who acquired HIV vertically. Strategies to improve survival among ALHIV, including adolescent-tailored care and support for adherence to ART, are urgently needed.