Validity of electronic hospital discharge prescription records as a source of medication data for pharmacoepidemiological research

Background: The advent of hospital electronic medical records (EMRs) with electronic prescribing provides considerable opportunity for pharmacoepidemiological research. However, validity of EMR prescribing data for research purposes is not well established. Validity concerns the percentage of cases in which medications and characteristics (name, type, formulation, dose) are true when verified with an independent data source. This study evaluated the validity of EMR discharge prescription data within the Eastern Health hospital network in Melbourne, Australia. Methods: A random sample of patients were selected who had a diagnosis of atrial fibrillation (AF) and were prescribed at least five medications. Prescription records from 2012 to 2015 were compared with pharmacy dispensing and hospital medical records (reference standards). Medication name, dose, directions and route of administration were compared. Discrepancies between data sources were categorized as omissions, additions, discrepancies in dose, medication form or route of administration or discrepancies in reordering. Sensitivities and 95% confidence intervals (CIs) for intended medication exposure were estimated for therapeutic classes. Results: A total of 5724 prescription orders for 479 patients for whom reference standards were available were included. There were 163 discrepancies (2.8%) between prescription records and reference standards. Additions were the most common data discrepancy (n = 65; ~1.1% of total prescriptions evaluated), followed by discrepancies in reordering (n = 34; 0.59%). Sensitivities for intended patient exposure to a medication for each therapeutic class at the first level of the Anatomical Therapeutic Chemical (ATC) classification system were between 97% and 100%. The genitourinary system and sex hormone level of the ATC system demonstrated the lowest sensitivity, (97.3%; 95% CI 92.0%–100%) and the cardiovascular system level demonstrated the highest sensitivity (99.9%; 95% CI 99.7%–100%). Conclusion: EMR discharge prescription records for patients with AF are a valid information source for conducting pharmacoepidemiological research within Eastern Health in Melbourne, Australia. Further studies in different regions, countries and patient cohorts are required to establish validity of hospital EMR prescription records for pharmacoepidemiological research.