Rationale, design, and methodology of the EPIC (Epidemiology of Polypharmacy and Potential Drug-Drug Interactions in Elderly Cardiac Outpatients) study.

The aim of this study is to assess the prevalence of polypharmacy, inappropriate drug use, and drug-drug interactions (DDIs) in elderly patients presenting at outpatient cardiology clinics in Turkey. The EPIC (Epidemiology of Polypharmacy and Potential Drug-Drug Interactions in Elderly Cardiac Outpatients) study will be an observational, real-world, multicenter study conducted to evaluate DDIs and polypharmacy in elderly cardiac outpatients. All consecutive patients (aged ≥65 years) admitted to outpatient cardiology clinics between July 30, 2018 and July 30, 2019 who provide written, informed consent will be enrolled. A total of approximately 5000 patients are to be enrolled in this non-interventional study. All of the data will be collected at one point in time and current clinical practice will be evaluated (ClinicalTrials.gov NCT03370523). Patient demographics, comorbid disease characteristics, laboratory test results, and details of medication use will be collected using self-reports and medical records. The severity of comorbid disease will be recorded and scored according to Charlson Comorbidity Index (CCI) and patients will be divided into 3 groups: mild, those with a CCI score of 1-2; moderate, those with a CCI score of 3-4; and severe, those with a CCI score of ≥5. Polypharmacy will be defined as the use of 5 or more medications at one time. DDIs will be determined using the Lexicomp Online drug interaction screening tool and potentially inappropriate medications will be defined based on the 2015 update of the Beers Criteria for Potentially Inappropriate Medication Use in Older Adults. Severe drug interactions will be defined as those in category D or X. EPIC will be the first large-scale study in Turkey to evaluate polypharmacy, potentially inappropriate medications, and DDIs in elderly cardiac outpatients in a real-world clinical setting.