Nature and frequency of drug therapy alerts generated by clinical decision support in community pharmacy

Purpose: The purpose of this study is to investigate the nature, frequency, and determinants of drug therapy alerts generated by a clinical decision support system (CDSS) in community pharmacy in order to propose CDSS improvement strategies. Methods: This is a retrospective analysis of dispensed drugs and drug therapy alerts generated by a CDSS in community pharmacies. Results: Data were extracted from the CDSS of 123 community pharmacies. After taking a 10% random sample of patients with a prescription in the period August 2013-July 2014, 1672169 dispensed prescriptions from 81742 patients were included in the analysis. Of all processed prescriptions, 43% led to one or more drug safety alerts, most frequently drug-drug interaction alerts (15% of all prescriptions), drug-disease interaction alerts (14%), duplicate medication alerts (13%), and dosing alerts (7%). The majority of prescriptions with alerts (80%) were clustered in a minority of patients (16%). The therapeutic drug group of the prescribed drug was the most important determinant of alert generation. Prescriptions for antithrombotic agents accounted for 9.4% of all prescriptions with an alert, beta-blocking agents for 7.5% and angiotensin-converting-enzyme inhibitors for 6.1%. Discussion and conclusion: The investigated CDSS in Dutch community pharmacy generated one or more drug therapy alerts in nearly half of the processed prescriptions. The majority of alerts were concentrated in a minority of therapeutic drug groups and patients. To decrease the alert burden, CDSS improvements should be directed at the prioritization and integration of drug therapy alerts for these therapeutic groups within patients.