# Medication Errors Detected in Primary Health Care after Hospital Discharge
## 1 Introduction  
Concerns about the adverse effects of the drugs used in health care are increasing among healthcare professionals [1, 2, 3]. Trying to prevent them, the World Health Organization (WHO) reported specific measures on the safe usage of drugs, describing the process called Medication Reconciliation [1]. In 2017, this same organization highlighted that improving the communication at the different healthcare transition points was essential to avoid harm originated by drugs [4]. Healthcare transitions do generate a risk for patient safety, as medication errors are likely to occur, due to the lack of communication among healthcare professionals, and the potential loss of information [4, 5, 6]. The reconciliation of medication contrasts the patients' medication to the medication prescribed after a healthcare transition, to analyze and solve discrepancies and medication errors [7, 8, 9, 10]. A medication error is a preventable event, related to the prescription and the use of drugs, that can cause harm to patients. It can be related to clinical and procedural issues but, in most cases, it is due to the use of inappropriate drugs [2, 3, 4, 9]. These errors cost billions of euros and an incalculable human cost [9]. It is estimated that, in the European Union, up to 12% of patients admitted to hospitals suffer from adverse effects related to drugs [11]; and 40-60% of the patients' medications can show discrepancies at hospital discharge [12]. To identify and correct medication discrepancies, the National Institute for Health and Care Excellence (NICE), the Accreditation Canada, and the Joint Commission propose to perform medication reconciliation in healthcare transitions [2, 5, 8, 13]. In Spain, 9.4% of patients admitted to hospitals have had adverse effects, and one-third of them could be related to the use of medication. It is estimated that 25.6% of these errors could have been prevented [14; 15]. For this reason, the Spanish Ministry of Health elaborated the Patient security strategy guide, which included the reconciliation of medication as a step between hospital and primary health care transition [3]. As poly-medicated and chronic patients are more susceptible to experiencing medication errors, in these specific groups is more relevant to perform the reconciliation of medication at any healthcare transition [7; 12; 13; 16; 17]. The reconciliation of medication is performed by primary health care physicians, following a structured and systematic method, using a computer program provided by the Andalusian Health Service. This tool has a checklist, which guarantees the adherence to the protocol, that must be fulfilled by the physicians. All the discrepancies must be recorded. The conciliations performed are recorded in a database that is subsequently analyzed. The process of conciliation is based on a three-step methodology, endorsed by various national and international institutions [12]. In the first step, a full list of the medication is obtained from the digital medical records. This list includes dosages, posology, and dosage form. A personal interview with the patient or its caregiver, can also be performed. The second step compares that medication list with the new prescriptions performed at the hospital discharge, to find and solve potential discrepancies. The medication errors, considered as standard to perform this analysis, are the following: medication omission, contraindicated medication, discrepancies in dosages, drug interactions, and duplicated therapeutics [17]. In the third step, the physician informs the patients about the modifications performed in their medication [11; 12; 13]. Involving the patients in the management of their medication increases their safety and their adherence to the treatment [18]. Nevertheless, few studies have analyzed the process of medication reconciliation in the primary health care context.