Clopidogrel use and early outcomes among older patients receiving a drug-eluting coronary artery stent

Abstract

Background: Clopidogrel use after drug-eluting stent (DES) coronary artery implantation is essential for the prevention of early in-stent thrombosis, but clopidogrel use among older DES recipients has not been widely studied. We sought to identify characteristics associated with failure to fill a clopidogrel prescription and to examine the relationship between a clopidogrel prescription fill and hospitalization for acute myocardial infarction (AMI) or death.

Methods and results: This study was a retrospective analysis of administrative data (20% sample) of 15 996 Medicare Part D enrollees who received a DES in 2006 to 2007. We modeled the adjusted probability and odds of clopidogrel prescription fill within 7 and 90 days of discharge and its association with AMI hospitalization or death. Of the study sample, 19.7% did not fill a clopidogrel prescription within 7 days of discharge, falling to 13.3% by day 90. The adjusted probability of filling a clopidogrel prescription within 7 or 90 days of discharge was lower for patients with dementia (20.2% less likely; 95% CI, 10.4%-30.1%), depression (10.7% less likely; 95% CI, 6.9%-14.5%), age >84 years compared to age 65 to 69 years (10.6% less likely; 95% CI, 8.6%-12.7%), black race (6.6% less likely; 95% CI, 4.2%-9.0%), intermediate levels of medication cost share (5.2% less likely; 95% CI, 2.9%-7.6%), and female sex (3.3% less likely; 95% CI, 2.1%-4.5%). It was higher for patients initially hospitalized for an AMI (12.5% more likely; 95% CI, 11.3%-13.6%). Failure to fill a clopidogrel prescription within 7 days of discharge was associated with a higher adjusted odds ratio of death during days 8 to 90 (2.44; 95% CI, 1.76-3.38) but was not associated with an increased risk of hospitalization for AMI.

Conclusions: One in 5 patients failed to fill a prescription for clopidogrel at 7 days after DES placement, and 1 in 7 failed to do so by 3 months. Individual characteristics available at the time of hospital discharge were associated with a clopidogrel prescription fill. Those characteristics most strongly associated with nonadherence, including age >84 years, not having an AMI, depression, and dementia, may guide clinicians and health systems seeking to target this high-risk population and improve health outcomes after percutaneous coronary intervention.

Figure 1

Cohort Creation Flow Chart