LAUSR

Background: Medication Reconciliation leads to quick detection of drug‐related problems, studies in ambulatory care are scarce. The recently introduced Medication Plan in Germany serves as an ideal basis for Medication Reconciliation. Objective: The study aim was to provide accurate data on the magnitude of discrepancy between the prescription and the actually taken medicine. Clinical relevance of discrepancies was assessed to estimate the impact on medication safety. Methods: Patients were assessed at home, data was reconciled with the physician's documentation. Discrepancies were analyzed and stratified. Risk for hospitalization, risk for falls and the potential for drug‐drug interactions was estimated based on literature. Drugs were tested for its origin and grouped to indication clusters. Detected DRPs at a Medication Review were linked to the results at Medication Reconciliation. Results: Medication of 142 elderly patients from 12 practices was reconciled. 1498 drugs were found at the home assessment, 1099 (73.4%) of which were detected in the physician's documentation. 94.4% of the patients were affected by discrepancies. A total of 2.8 ± 2.4 drugs was undocumented per patient. 26.6% of missing drugs were prescribed by medical specialists, 42.5% of drugs of unknown origin were prescription drugs. 53.9% of the patients used a undocumented drug, which carried a high risk for hospitalization. 23.1% of the drugs not covered were used for treatment of cardiovascular diseases. 65.8% of the differing drugs caused at least one DRP. Conclusion: A high discrepancy between the drugs used by the patient and the medication documented by the primary care physician could be found. Relating drugs had a profound systemic effect and were particular relevant to medication safety. Many drugs were prescription drugs. The majority of differing drugs caused DRPs. A collaborative Medication Reconciliation as part of a Medication Management could compile the entire medication and increase patient safety HIGHLIGHTSPrimary care physicians' documentation was reconciled with patients' medication assessed at home.Discrepancies were found at virtually all study patients.Undocumented drugs were highly relevant to patient safety and led to actual DRPs in every second patient.Interprofessional collaboration could reveal and solve discrepancies in the patients' medication and improve drug safety.