Insight into the Use and Outcomes of Anti-Platelet Agents in Patients with Acute Coronary Syndrome

In patients who have received percutaneous coronary intervention (PCI) for the treatment of acute coronary syndrome (ACS), three anti-platelet agents were similarly used to reduce further cardiovascular complications. Of them the newer agents, prasugrel and ticagrelor, showed better efficacy profiles in a controlled setting compared to clopidogrel. With regard to the real-world practice in the anti-platelet agent use, however, there has been limited evidence. This research project was designed to fill in the research gap using an insurance claims database. During the period between 2009 and 2013, clopidogrel use remained a dominant option in commercially insured ACS-PCI patients, especially in patients with risk factors of further complication. After being launched, ticagrelor did not take up the US market share of clopidogrel, but instead replaced prasugrel. Clopidogrel use was significantly associated with the presence of comorbid conditions or risks of future complications and mortality. The odds of using ticagrelor vs. prasugrel increased with a history of cerebrovascular events. Selection of anti-platelet agent was not associated with a significant difference in total medical expenditure. Treatment effects on economic outcomes were separately measured in patients who enrolled in the health plan over a 6-month post ACS discharge period and in those who maintained their initial treatment over the 6 months. Regression analyses found that the use of newer agents vs. clopidogrel increased medication cost over the 6-month period, which is mainly attributed to the increase in the expenditure on the cardiovascular medication. However, when we looked at the total medical cost, the estimated difference between the costs in the newer agent users and in the clopidogrel users was insignificant. The analysis of resource utilization demonstrated that there was a significant decrease in the rate of hospital admission with the use of newer agents, which explained how the increase in the medication cost could be cancelled out. Between prasugrel and ticagrelor, there was not a statistically significant difference in the hazard rates of all-cause and MI related hospitalization from 30-day to 365-day post ACS-PCI discharge periods. The hazard ratios were corresponding to the effect of drug selection on healthcare utilization estimates. In general, association measures did not consistently favor one over the other. Although the results and conclusions were accompanied by the general limitations of retrospective analysis and suffered from sample size issues, the study helped to fill a gap which have not been and could not be investigated in a controlled setting.