Pharmacoeconomic impact of non-compliance with statins

Abstract

There are numerous studies examining the pharmacoeconomic impact of HMG-CoA reductase inhibitor (statin) therapy on healthcare costs and outcomes. A recently published review demonstrated that the cost-benefit of these agents depends primarily on the risk of developing a coronary event. That is, as the risk of a coronary event increases, the cost-effectiveness ratio decreases. The typical cost per life-year saved (LYS) ranged from USD 1800 to USD 40,000 in patients with pre-existing coronary artery disease (CAD) and from USD 15,000 to > USD 1 million per LYS in patients without pre-existing CAD. The literature is sparse on the pharmacoeconomics of medication non-compliance in patients taking statin medications. Data from two studies suggest that >75% compliance results in decreased coronary events such as myocardial infarction. However, retrospective database analyses indicate that the average compliance rate hovers around the 65% mark. Many of the studies discuss medication non-compliance as a factor, but do not independently analyse compliance pharmacoeconomically. We examined the pharmacoeconomic impact of non-compliance using published studies that contained pharmacoeconomic data and/or compliance data. In general, we used the placebo arm of these published studies as the surrogate marker for complete non-compliance. The results suggest that for almost 100% compliance versus initial non-compliance, the cost effectiveness of statin medications ranges from USD 4500 to over USD 250,000 per LYS depending on patient age, presence or absence of risk factors and whether the statin is being used for primary or secondary prevention. Alternate-day or weekly dosing studies were also used to examine the impact of compliance on cost and health outcomes. Alternate-day dosing represented 50% compliance and weekly dosing 29% compliance. Less than full compliance had the expected effect of worse health outcomes and lower drug costs. However, the studies were small and not designed as true pharmacoeconomic studies looking at the relationship between medication compliance and cost. The results of this review suggest that there needs to be further examination of the relationship between compliance with statins and cost effectiveness, and studies need to include compliance in their data collection and analysis.