The modeled lifetime cost-effectiveness of published adherence-improving interventions for antihypertensive and lipid-lowering medications

Abstract

Objective: We sought to compare the cost-effectiveness of different interventions that have been shown to improve adherence with antihypertensive and lipid-lowering therapy, by combining a burden of nonadherence model framework with literature-based data on adherence-improving interventions.

Methods: MEDLINE was reviewed for studies that evaluated ≥1 adherence intervention compared with a control, used an adherence measure other than self-report, and followed patients for ≥6 months. Effectiveness was assessed as Relative Improvement, ratio of adherence with an intervention versus control. Costs, standardized to 12 months and adjusted to 2007 US$, and effectiveness estimates for each intervention were entered into a previously published model designed to measure the burden of nonadherence with antihypertensive and lipid-lowering medications, in a hypertensive population. Outputs included direct medical costs and incremental costs per quality-adjusted life-year (QALY) gained.

Results: After screening, 23 eligible adherence-improving interventions were identified from 18 studies. Relative Improvement ranged from 1.13 to 3.60. After eliminating more costly/less effective interventions, two remained. Self-monitoring, reminders, and educational materials incurred total health-care costs of $17,520, and compared with no adherence intervention, had an incremental cost-effectiveness ratio (ICER) of $4984 per QALY gained. Pharmacist/nurse management incurred total health-care costs of $17,896, and versus self-monitoring, reminders, and education had an ICER of $6358 per QALY gained.

Conclusions: Of published interventions shown to improve adherence, reminders and educational materials, and a pharmacist/nurse management program, appear to be cost-effective and should be considered before other interventions. Understanding relative cost-effectiveness of adherence interventions may guide design and implementation of efficient adherence-improving programs.