The clinical and economic burden of nonadherence with antihypertensive and lipid-lowering therapy in hypertensive patients.

OBJECTIVE: We sought to determine lifetime costs, morbidity, and mortality associated with varying adherence to antihypertensive and 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statin) therapy in a hypertensive population.
METHODS: A model was constructed to compare costs and outcomes under three adherence scenarios: no treatment, ideal adherence, and real-world adherence. Simulated patients' characteristics matched those of participants in the Anglo-Scandinavian Cardiac Outcomes Trial-Lipid-Lowering Arm and event probabilities were calculated with Framingham Heart Study risk equations. The real-world adherence scenario employed adherence data from an observational study of a US population; risk reductions at each level of adherence were based on linear extrapolations from clinical trials. Outputs included life expectancy, frequencies of primary and secondary coronary heart disease and stroke, and direct medical costs in 2006 US$. The incremental cost per life-year gained and incremental cost per event avoided were calculated comparing the three adherence scenarios.
RESULTS: Mean life expectancy was 14.73 years (no-treatment scenario), 15.07 (real-world adherence), and 15.49 (ideal adherence). The average number of cardiovascular events per patients was 0.738 (no treatment), 0.610 (real-world adherence), and 0.441 (ideal adherence). The incremental cost of real-world adherence versus no treatment is $30,585 per life-year gained, and ideal adherence versus real-world adherence is $22,121 per life-year gained.
CONCLUSIONS: Hypertensive patients taking antihypertensive and statin therapy at real-world adherence levels can be expected to receive approximately 50% of the potential benefit seen in clinical trials. Depending on its cost, the incremental benefits of an effective adherence intervention program could make it an attractive value.