Using age-specific mortality of HIV infected persons to predict Anti-Retroviral Treatment need: a comparative analysis of data from five African population-based cohort studies

Objectives To present a simple method for estimating population-level anti-retroviral therapy (ART) need that does not rely on knowledge of past HIV incidence. Methods A new approach to estimating ART need is developed based on calculating age-specific proportions of HIV-infected adults expected to die within a fixed number of years in the absence of treatment. Mortality data for HIV-infected adults in the pre-treatment era from five African HIV cohort studies were combined to construct a life table, starting at age 15, smoothed with a Weibull model. Assuming that ART should be made available to anyone expected to die within 3 years, conditional 3-year survival probabilities were computed to represent proportions needing ART. The build-up of ART need in a successful programme continuously recruiting infected adults into treatment as they age to within 3 years of expected death was represented by annually extending the conditional survival range. Results The Weibull model: survival probability in the infected state from age 15 = exp(-0.0073 x (age - 15)1.69) fitted the pooled age-specific mortality data very closely. Initial treatment need for infected persons increased rapidly with age, from 15% at age 2024 to 32% at age 4044 and 42% at age 6064. Overall need in the treatment of naive population was 24%, doubling within 5 years in a programme continually recruiting patients entering the high-risk period for dying. Conclusion A reasonable projection of treatment need in an ART naive population can be made based on the age and gender profile of HIV-infected people.