Simulating the provision of antiretroviral therapy in Zambia

Zambia has over 1.9 million HIV-infected people and is one of the countries hardest hit by the HIV pandemic. Limited information exists on the long-term survival and economic costs of antiretroviral therapy (ART) in the country. The study we describe here has two aims: 1. Provide better estimates for the long-term survival of people on ART; 2. Forecast the number of people on ART and the cost of providing ART in Zambia over the next decade. Survival analysis techniques have been used to estimate distributions for the time spent on ART using electronic records from the Zambian national database. We use Discrete Event Simulation to model the number of people on ART in Zambia and provide projections for the cost of providing ART in the future. HIV-infected patients enter the model when they commence ART and exit the system due to death, becoming lost to follow up or stopping treatment.