Identifying High-Risk Medication Prescriptions to Prevent Potentially Severe Adverse Drug Events in Primary-Care Patients with Chronic Multimorbidities: The Polychrome Study

Background: The association between multimorbidities and polypharmacy among elderly individuals is well documented, and polypharmacy has been shown to increase the risk of adverse drug events (ADEs). However, little information is available about the risks associated with the lifelong use of medications to treat chronic multimorbidities. Objective: To determine the prevalence and nature of high-risk prescriptions among primary-care patients with chronic multimorbidities. Methods: We studied a weighted stratified random sample of 105 prescriptions for different patients with chronic multimorbidities taken from the Polychrome database established using information from the French primary-care record database (Observatoire de la MédecineGénérale). A medication review was conducted to identify contra-indications and potential drug-drug interactions for each prescription. Results: Contra-indications were identified for 60 (57.1%) prescriptions, potential drug-drug interactions for 70 (66.7%), absolute contra-indications for 9 (8.6%), and inadvisable drug combinations for 11 (10.5%). In all, 19 (18.1%) different patients were at risk for major ADEs. Cardiovascular and nervous-system drugs contributed 66.2% of contra-indications and 69.3% of potential drug-drug interactions. Conclusions: This exploratory study confirms the high prevalence and potential seriousness of prescriptions at risk for ADEs in a population of primary-care patients with chronic multimorbidities. The high prevalence of interactions involving the cardiovascular and nervous systems indicates that efforts to improve prescription practices should target these two categories of conditions and drugs in patients with chronic multimorbidities.