INFORMING RESOURCE ALLOCATION DECISIONS IN HIV/AIDS: A CASE STUDY FOR BRITISH COLUMBIA, CANADA
Purpose: Interventions to improve HIV care may vary substantially in their ability to deliver good value for money. There is an urgent need to maximize the value of health spending by prioritizing cost-effective interventions and, more broadly, identifying an optimal mix of interventions. We consider hypothetical scenarios of increased uptake of HIV testing and treatment, and improved treatment retention to identify the most cost-effective public health strategy.
Method: We used a previously-validated dynamic compartmental HIV transmission model to project the costs, benefits and epidemiological outcomes of the HIV/AIDS epidemic in BC from 2015 to 2035 under six hypothetical scenarios: (1) current practice, characterized using all available population-level epidemiologic and economic data; (2) a 10% increase in the HIV testing rate; (3) a 10% increase in treatment uptake; (4) a 25% decrease in the rate of treatment discontinuation; (5) interventions in scenarios (2)+(3); and (6) interventions in scenarios (2)+(3)+(4). In this hypothetical exercise, costs and effectiveness of the various interventions was assumed equal across HIV risk groups, the implementation of the interventions was at the provincial-level, and no budget constraint was imposed. Total HIV incidence, mortality, present-valued costs (in 2014$CDN) and quality-adjusted life years (QALYs) were estimated for each scenario, while incremental cost-effectiveness ratios (ICERs) were calculated against scenario (1), as well as the next-most resource intensive strategy in the interest of identifying the most efficient strategy. Analyses were executed from a third party payer (TPP) perspective.
Result: Scenarios (2) – (6) were all highly cost effective (<1x GDP per capita) compared to actual practice. Strategies (3) and (4) were dominated by strategies (5) and (6) respectively. We found strategy (6) remained cost-effective compared to strategy (5), with an ICER of $30,351 per QALY gained. At an additional cost of $110M over the study timeframe (5.5M/year), jointly increasing HIV testing and treatment access and improving HAART retention resulted in 531 averted HIV cases, 115 averted deaths and an overall gain of 6,469 QALYs.
Conclusion: Despite significant prior investment and advances in HIV care in BC, we found interventions to further improve HIV testing and care were highly cost-effective. Further research is required to aid resource allocation decisions on the margin, in real-time, using the observed costs and effectiveness of such interventions as delivered within localized settings.