Initiation and duration of dual antiplatelet therapy after inpatient percutaneous coronary intervention with stent implantation in Germany: An electronic healthcare database cohort study.

BACKGROUND: Studies assessing the routine outpatient dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) in Germany are scarce. The aim of this study was (i) to investigate the initiation and duration of DAPT after inpatient PCI with stent implantation in Germany, and (ii) to identify factors associated with DAPT discontinuation during the recommended treatment period.

METHODS: This retrospective cohort study was based on data from a large German electronic healthcare database of the years 2004 to 2009. The study population comprised four groups of patients with acute coronary syndrome (ACS) or stable angina pectoris undergoing inpatient PCI with either bare metal stent (BMS) or drug eluting stent (DES) implantation between 2005 and 2008. Initiation of outpatient DAPT within a period from 100 days before the PCI to 60 days after the PCI was ascertained. Time until end of treatment was analysed using the Kaplan-Meier method. Factors potentially associated with DAPT discontinuation, like sex, age, cardiovascular comorbidity, contraindications, and other antithrombotic drugs were analysed in a Cox proportional hazard model.

RESULTS: The cohort comprised 37,001 patients. Depending on the type of stent and the indication for the PCI, DAPT was initiated in 85 % (ACS/BMS) and 95 % (AP/DES) of all patients. Of those, 12 % (AP/DES) and 64 % (ACS/BMS) discontinued DAPT during the recommended treatment duration. An age of over 80 years (OR 1.2-1.5 compared to patients aged 0-49 years) and the use of phenprocoumon (OR 2.7-5.0 compared to no phenprocoumon) were associated with an increased risk of DAPT discontinuation.

CONCLUSIONS: A high proportion of patients with coronary artery disease undergoing inpatient PCI with stent implantation received DAPT. However, DAPT discontinuation during the recommended time span was frequent, particularly in patients suffering from ACS. On the other hand, especially patients with AP and DES were often treated longer than recommended.