Impact of Polypharmacy on Adherence to Evidence-Based Medication in Patients who Underwent Percutaneous Coronary Intervention

Background: The primary objective of this study was to evaluate the impact of polypharmacy on primary and secondary adherence to evidence-based medication (EBM) and to measure factors associated with non-adherence among patients who underwent percutaneous coronary intervention (PCI). Methods: We conducted a retrospective analysis for patients who underwent PCI at a tertiary cardiac care hospital in Qatar. Patients who had polypharmacy (defined as >= 6 medications) were compared with those who had no polypharmacy at hospital discharge in terms of primary and secondary adherence to dual antiplatelet therapy (DAPT), beta-blockers (BB), angiotensin converting enzyme inhibitors (ACEIs) and statins. Results: A total of 557 patients (mean age: 53 +/- 10 years; 85%; males) who underwent PCI were included. The majority of patients (84.6%) received >= 6 medications (polypharmacy group) while only 15.4% patients received <= 5 medications (non-polypharmacy group). The two groups were comparable in term of gender, nationality, socioeconomic status and medical insurance. The non-polypharmacy patients had significantly higher adherence to first refill of DAPT compared with patients in the polypharmacy group (100 vs. 76.9%; p=0.001). Similarly, the non-polypharmacy patients were significantly more adherent to secondary preventive medications (BB, ACEI and statins) than the polypharmacy group. Conclusion: In patients who underwent PCI, polypharmacy at discharge could play a negative role in the adherence to the first refill of EBM. Further studies should investigate other parameters that contribute to long term non-adherence.