Cognitive Errors in Reconciling Complex Medication Lists.

Discrepancies between multiple electronic versions of patient medication records contribute to adverse drug events. Regular reconciliation increases their accuracy but is often inadequately supported by EHRs. We evaluated two systems with conceptually different interface designs for their effectiveness in resolving discrepancies. Eleven clinicians reconciled a complex list of 16 medications using both EHRs in the same standardized scenario. Errors such as omissions to add or discontinue a drug or to update a dose were analyzed. Clinicians made three times as many errors working with an EHR with lists arranged in a single column than when using a system with side-by-side lists. Excessive cognitive effort and reliance on memory was likely a strong contributing factor for lower accuracy of reconciliation. As errors increase with task difficulty, evaluations of reconciliation tools need to focus on complex prescribing scenarios to accurately assess effectiveness, error rate and whether they reduce risk to patient safety.