Reconcilable differences: correcting medication errors at hospital admission and discharge

Background: Medication errors at the time of hospital admission and discharge are common and can lead to preventable adverse drug events. The objective of this study was to describe the potential impact of a medication reconciliation process to identify and rectify medication errors at the time of hospital admission and discharge. Methods: Sixty randomly selected patients were prospectively enrolled at the time of admission to a Canadian community hospital. At admission, patients' medication orders were compared with preadmission medication use based on medication vials and interviews with patients, caregivers, and/or outpatient healthcare providers. At discharge, pre-admission and in-patient medications were compared with discharge orders and written instructions. All variances were discussed with the prescribing physician and classified as intended or unintended; unintended variances were considered to be medication errors. An internist classified the clinical importance of each unintended variance. Results: Overall, 60% (95% CI 48 to 72) of patients had at least one unintended variance and 18% (95% CI 9 to 28) had at least one clinically important unintended variance. None of the variances had been detected by usual clinical practice before reconciliation was conducted. Of the 20 clinically important variances, 75% (95% CI 56 to 94) were intercepted by medication reconciliation before patients were harmed. Discussion: Unintended medication variances at the time of hospital admission and discharge are common and clinically important. The medication reconciliation process identified and addressed most of these unintended variances before harm occurred. In this small study, medication reconciliation was a useful method for identifying and rectifying medication errors at times of transition. Reconciliation warrants broader evaluation.