In 2014, Accreditation Canada, a not-for-profit organization that evaluates healthcare institutions on quality of care, introduced a requirement for emergency departments (EDs) to identify patients at high-risk for drug-related morbidity, so that medication management interventions can be targeted toward high-risk groups. We validated a previously derived clinical decision rule allowing triage nurses to identify high-risk patients and refer them to clinical pharmacists for medication review aimed at detecting and mitigating adverse drug events (ADEs). The rule’s variables did not require refinement, and now that its performance has been validated in a new sample of patients, it can be implemented in EDs nationally to assist institutions in complying with Accreditation Canada standards.

Introduction: ADEs, unintended and harmful effects of medications, are a leading cause of ED visits, yet 50% of cases are missed. We derived a clinical decision rule to identify patients at high-risk for ADEs. Our aim was to validate the ADE rule by determining its sensitivity and specificity in a new sample.

Methods: We conducted a prospective study at the Civic Campus of The Ottawa Hospital. We combined our results with 2 separately funded BC hospitals. We enrolled adult ED patients taking at least one medication within 2 weeks. Nurses completed the clinical decision rule, and both a research pharmacist and physician assessed each patient for ADEs blinded to the nursing decision rule data. Disagreements were adjudicated by an independent committee. The primary outcome was an ADE resulting in a change in medical management, hospital admission or death. We calculated the rule’s sensitivity, specificity, and the proportion of patients screening positive.

Results: Among 1529 patients, 191 (12.9%, 95%CI 11.2-14.6%) had at least one ADE. The rule, consisting of: having a pre-existing medical condition or taken antibiotics within one week; and, age >80 or having a medication change within 28 days, had a sensitivity of 91.1% (95%CI 86.3%- 94.7%) and a specificity of 38.1% (95%CI 35.5%-40.8%). The proportion of patients screening positive was 39.9%. Amongst Ottawa patients (n=418), the rule had a sensitivity of 96.6% (95%CI 88.1-99.6%) and a specificity of 39.7% (95%CI 34.6-45.0%), and 54.9% of patients screened positive .

Conclusion: The rule was sensitive in identifying adult ED patients presenting with ADEs while maintaining reasonable specificity.  The rule may help identify patients who may benefit from evaluation by a clinical pharmacist in the ED, and will help institutions meet current Accreditation Canada standards.