INTRODUCTION

Cardiovascular disease (CVD) is the leading cause of death in the United States, and high cholesterol is a leading risk factor for CVD. While statins are effective at reducing cholesterol, they are frequently underused in patients at highest risk of CVD. The objective of this study was to identify interventions which may improve adherence to statins and to assess their cost effectiveness within the US Medicare population.

METHODS

A literature review was undertaken to identify interventions to improve adherence in patients with CVD at highest risk of a recurrent event and to quantify non-adherence and the consequences of non-adherence to statins in this population. A Markov cost-utility model was developed to assess the cost effectiveness of these interventions.

RESULTS

Ten adherence interventions were identified in the literature, with 6 demonstrating statistically significant improvement in adherence. The six interventions were disease management, interactive voice response, nurse counselling, discharge letter, nurse/dietician counselling and electronic pill bottle with feedback. The model found the cost effectiveness of an intervention was highly dependent on its effectiveness and costs. Incremental cost effectiveness ratios ranged from $27,545/QALY for discharge letter with large adherence gain to $130,399/QALY for disease management program with small adherence gain.

CONCLUSION

Some interventions to improve adherence have been shown to be effective, but little attention has been paid to the costs. Further studies on adherence interventions should include economic evaluations.