Antiretroviral Treatment Outcomes amongst Older Adults in a Large Multicentre Cohort in South Africa

Increasing numbers of patients are starting antiretroviral treatment (ART) at advanced age or reaching advanced age while on ART. We compared baseline characteristics and ART outcomes of older adults (aged ≥55 years) vs. younger adults (aged 25–54 years) in routine care settings in South Africa. Methods A multicentre cohort study of ART-naïve adults starting ART at 89 public sector facilities was conducted. Mortality, loss to follow-up (LTFU), immunological and virological outcomes until five years of ART were compared using competing-risks regression, generalised estimating equations and mixed-effects models. Results 4065 older adults and 86,006 younger adults were included. There were more men amongst older adults; 44.7% vs. 33.4%; RR = 1.34 (95% CI: 1.29–1.39). Mortality after starting ART was substantially higher amongst older adults, adjusted sub-hazard ratio (asHR) = 1.44 over 5 years (95% CI: 1.26–1.64), particularly for the period 7–60 months of treatment, asHR = 1.73 (95% CI: 1.44–2.10). LTFU was lower in older adults, asHR = 0.87 (95% CI: 0.78–0.97). Achievement of virological suppression was greater in older adults, adjusted odds ratio = 1.42 (95% CI: 1.23–1.64). The probabilities of viral rebound and confirmed virological failure were both lower in older adults, adjusted hazard ratios = 0.69 (95% CI: 0.56–0.85) and 0.64 (95% CI: 0.47–0.89), respectively. The rate of CD4 cell recovery (amongst patients with continuous viral suppression) was 25 cells/6 months of ART (95% CI: 17.3–33.2) lower in older adults. Conclusions Although older adults had better virological outcomes and reduced LTFU, their higher mortality and slower immunological recovery warrant consideration of age-specific ART initiation criteria and management strategies.