Cost-effectiveness of a novel strategy of HIV/AIDS care in Armed Forces: A stochastic model with Monte Carlo simulation

Despite the initial success of HIV/AIDS policy, an increasing number of patients are failing the first-line antiretroviral therapy (ART) each year and the failure rates are increasing. There is a need for identification of novel strategies to reduce failure rates. The aims of the study are (1) to design a novel strategy to reduce ART failure rates and (2) to create a stochastic model using Monte Carlo (MC) simulation comparing the novel strategy with existing strategy.

A novel strategy based on annual plasma viral load testing and resistance testing for HIV treatment at baseline and at the time of failure was designed. A cohort of 1000 patients each was created for the existing strategy and a novel strategy. Assumptions were included from Indian studies and own data. The two strategies were compared over 20 years of follow-up using stochastic modeling and MC simulation was done for death rates, failure rates, and cost-effectiveness analysis. SimVoi add-in software for MS Excel was used for simulations. Student's t-tests were performed for comparing continuous variables, and the cumulative rates for various outcomes were plotted using Kaplan-Meier analysis.

The novel strategy resulted in lower mortality over a 20-year period (279.9 + 7.13 deaths vs 130.43 + 6.03 deaths) with incremental cost per life saved at Rs 32,925 per year. Incremental cost-effectiveness ratio cost per quality-adjusted life year was Rs 1.33 lakhs/annum at constant rate of discounting and just under Rs 90,000 per annum using differential discounting.

Armed Forces are likely to benefit by adopting the novel strategy that is cost-effective with a significant mortality benefit.