OBJECTIVES: Medication adherence is crucial for predicting cardiovascular disease (CVD) outcomes in patients requiring secondary prevention. Despite the importance of improving adherence, the permissible cost of undertaking this at the population-level is unclear. This study aims to assess the permissible cost of increasing medication adherence in secondary CVD prevention.

METHODS: A threshold analysis based on a cohort-level simulation of secondary CVD prevention was performed for valuation of potentially improving medication adherence to optimal level, based on a meta-analysis of 51 randomized controlled trials. A Markov model was developed to project both direct medical, non-medical, and indirect (Mexico only) costs in 2022 USD and outcomes of those patients in Mexico and Thailand. Analyses were performed using a societal perspective with a lifetime time horizon. We estimated permissible cost of increasing medication adherence for cost saving and cost-effectiveness, based on willingness-to-pay (WTP) threshold of each country. Sensitivity analyses were performed.

RESULTS: Improving adherence to the optimal level reduced CVD events by 40 in Mexico and 34 in Thailand per 1000 patients. This improvement resulted in 0.60 and 0.84 life-year gained, and 0.59 and 0.68 quality-adjusted life years (QALY) gained, in Mexico and Thailand, respectively. The threshold analysis indicated that the permissible cost per patient per year for cost saving was $30 in Mexico and $13 in Thailand. In Mexico, permissible cost per patient per year for being cost-effective was $509, given the WTP threshold per life-year. In Thailand, this estimate was $242 annually, considering a WTP of $4,994 per QALY gained. Probabilistic sensitivity analysis demonstrated a probability of cost saving of 100% in Mexico and 93% in Thailand.

CONCLUSIONS: This study showed the economic value of improving medication adherence in secondary CVD prevention. These findings support the implementation of strategies to enhance medication adherence such as introduction of digital technologies or programs leading to behavior changes.