The medication discrepancy taxonomy (MedTax): The development and validation of a classification system for medication discrepancies identified through medication reconciliation

Background: Medication discrepancies directly impact patient safety and can adversely impact quality of care and resource utilization at transitions of care. Objectives: To develop a common nomenclature and taxonomy for classifying and reporting medication discrepancies and to assess the content validity and reliability of the taxonomy. Methods: The taxonomy was developed following a multi-stage process. The content of the taxonomy was then assessed using expert opinion through a two-round modified Delphi process. The expert panel comprised 10 experts who were selected based on pre-defined selection criteria. Six experienced pharmacists were then invited to classify medication discrepancies from a number of fictitious cases (adapted from authentic cases) using the taxonomy. Results: The medication discrepancy taxonomy (MedTax) comprises 12 main types and 28 sub-types of discrepancies. A set of operational instructions and definitions to aid the use of the taxonomy was formulated. The overall Average content validity index (Ave-CVI) was 0.93 and interrater reliability was 0.67 (multirater kappa free), indicating substantial agreement. An excellent internal consistency of the taxonomy was established (Kuder-Richardson Formula 20 (KR-20) = 0.92). Conclusions: A content valid and reliable taxonomy for classifying medication discrepancies was developed. The MedTax may be used to classify medication discrepancies identified following medication reconciliation services. The clear and consistent reporting of medication discrepancies arising from medication reconciliation services may be of value to policy makers, healthcare professionals and researchers, when evaluating such services. The MedTax was designed to fill an essential void in global endeavors to reinforce standardization of medication reconciliation practices and to improve medication safety across transitions of care.