(145) The European Drug-Drug Interaction (EuroDDI) study protocol: a cross country comparison of the prevalence of drug-drug interactions in the older community-dwelling population
PhD Candidate School of Population Health, RCSI University of Medicine and Health Sciences, Dublin 2, Ireland. Dublin, Ireland
Background: Drug-drug interactions (DDIs), highly prevalent amongst the elderly, can lead to avoidable medication-related harm. The cardiovascular and central nervous system (CNS) are commonly implicated. To date, there is no consensus on how to measure DDIs, making comparisons across countries challenging.
Objectives: By developing a common methodology, we aim to: (i) measure the prevalence of potential DDIs in older populations (aged ≥70 years) in three European countries; and (ii) describe differences across the countries.
Methods: This explorative study will apply a harmonised method of DDI identification and analysis using the WHO ATC classification system and national pharmacy claims data from three European countries (Ireland, Italy, Spain). Patients aged ≥70 years dispensed ≥2 medications during 2016 will be identified from each database. ‘Severe' cardiovascular and CNS DDIs (i.e. may result in a life-threatening event or permanent detrimental effect) will be identified using the British National Formulary and Stockley's Drug Interactions. Two separate lists of ‘severe’ DDIs, per medications reimbursed, will be applied to each database: (i) DDIs relevant to each individual country, and (ii) DDIs relevant to all three countries. DDIs will be defined as co-prescribed (same day) and concomitant (±7days).
Results: Descriptive statistics, including DDI prevalence and 95% confidence intervals will be reported for each country. Prevalence will be pooled and compared across countries using random effects models and meta-regression, where feasible.
Conclusions: The EuroDDI study will develop a harmonised method to measure and compare DDI prevalence across health-related databases in Europe.
