The impact of antiretroviral treatment on the age composition of the HIV epidemic in sub-Saharan Africa

Context: Recent studies have highlighted the increased risk of adverse outcomes among older patients on antiretroviral therapy (ART). We report on the associations between older age and adverse outcomes in HIV/AIDS antiretroviral programmes across 17 programmes in sub-Saharan Africa. Methods: We included data from nine countries: Central African Republic, Côte d’Ivoire, Democratic Republic of Congo, Ethiopia, Nigeria, Republic of Congo, Uganda, Zambia and Zimbabwe. We describe survival probability for progression to death and loss to follow-up for patients initiating ART aged less than 50 years and at least 50 years. Multivariate Cox proportional hazards models were used to assess the association between age (15–39, 40–49, 50–59, 60–69 and 70–94 years) and adverse outcomes adjusting for confounders identified a priori. Results: Our analysis included 17 561 patients followed for a median of 12 months. The majority (65%) were female and 6672 (38%) were severely immunosuppressed at baseline. Median age at ART initiation was 36.0 years (interquartile range 30.1–42.8); 11.4% of patients were aged at least 50 years. Median gain in CD4 cell count at 6 and 12 months was significantly higher in patients less than 50 years old compared with those at least 50 years (134 vs. 112 cells/μl at 6 months; 170 vs. 139 cells/μl at 12 months; both P < 0.001). In multivariate analysis, there was a significant increased risk of mortality beyond 3 months after ART initiation in all age groups of at least 40 years of age compared with less than 40 years [40–49 years adjusted hazard ratios (aHRs) 1.59, P < 0.001; 50–59 years aHR 1.58, P = 0.002; 60–69 years aHR 2.63, P < 0.001; 70–94 years aHR 3.64, P = 0.004). Conclusion: Older age groups represent an important proportion of the overall treatment cohort in these sub-Saharan Africa programmes, and risk of mortality increased as age increased. Future research should be directed at further understanding the reasons for higher mortality, and defining simple interventions that are feasible in highly under-resourced settings to allow for adapted follow-up and care approaches for older age groups