Background Medication errors are one of the main causes of morbidity in hospitalised patients. To minimise them at admission, it is convenient to perform a correct medication reconciliation that avoids discrepancies in the chronic treatment.

Purpose To assess the severity of the medication reconciliation errors (MRE) produced in the Emergency Department (ED) in patients admitted to the Acute Geriatric Unit (AGU).

To describe the incidence of the MRE detected.

Material and methods An observational, prospective study was conducted in a general hospital.

All patients admitted to the AGU between 1 October 2017 and 30 April 2018 were included, excluding those in palliative care.

The chronic treatment, collected by the pharmacist in an interview with the patient or main caregiver, was compared with the prescribed treatment in the ED.

We recorded the following variables: age, sex, number of chronic pathologies and chronic medications, type of discrepancy (justified or MRE), type of MRE according to a consensus document, whether the error reached the patient or not and its severity (using the NCCMERP classification with the collaboration of a specialist in geriatrics).

Results We included 351 patients, 238 females (67.8%), with a mean age of 92.7±3.9 years. The median of chronic pathologies was 5 (0–13) and of chronic medications 7 (1–24): 282 (80.3%) were polymedicated.

A total of 1473 discrepancies were identified in 328 (93.4%) patients: 300 discrepancies (20.4%) were considered as MRE in 151 (43%) patients, with an average of 2±0.7 errors per patient.

Regarding the severity of the MRE detected, 104 (34.7%) were classified as category C, 117 (39%) as category D and 27 (9%) as category E: 52 MRE (17.3%) were intercepted on time.

The most common MRE were omission errors, 149 (49.7%), wrong dose errors, 70 (23.3%) and commission errors, 37 (12.3%).

Conclusion Most of the MRE were not detected on time and reached the patient: one in 10 caused temporary damage (category E).

In almost half of the patients admitted to the AGU, at least one MRE was detected, being the most frequent omission errors.

These results reflect the need to implement medication reconciliation programmes in the ED.

References and/or acknowledgements No conflict of interest.