Translating Benzodiazepine Utilization Data into Meaningful Population Exposure: Integration of Two Metrics for Improved Reporting.

Drug utilization research on benzodiazepines remains important for measuring trends in consumption within and across borders over time for the sake of monitoring prescribing patterns and identifying potential population safety concerns. The defined daily dose (DDD) system by the World Health Organization (WHO) remains the internationally accepted standard for measuring drug consumption; however, beyond consumption, DDD-based results are difficult to interpret when individual agents are compared with one another or are pooled into a total class-based estimate. The diazepam milligram equivalent (DME) system provides approximate conversions between benzodiazepines and Z-drugs (i.e. zopiclone, zolpidem, zaleplon) based on their pharmacologic potency. Despite this, conversion of total dispensed benzodiazepine quantities into DME values retains diazepam milligrams as the total unit of measurement, which is also impractical for population-level interpretation. In this paper, we propose the use of an integrated DME-DDD metric to obviate the limitations encountered when the component metrics are used in isolation. Through a case example, we demonstrate significant change in results between the DDD and DME-DDD method. Unlike the DDD method, the integrated DME-DDD metric offers estimation of population pharmacologic exposure, and enables superior interpretation of drug utilization results, especially for drug class summary reporting.