Toward safer prescribing: evaluation of a prospective drug utilization review system on inappropriate prescriptions, prescribing patterns, and adverse drug events and related health expenditure in South Korea

Objectives: This study aimed to evaluate the effect of the prospective drug utilization review (DUR) system introduced in Korea in December 2010 as a real-time method to improve patient safety, in terms of changes in prescribing practices, adverse drug events (ADEs), and ADE-related healthcare expenditure, using non-steroidal anti-inflammatory drugs (NSAIDs) and their common ADEs as a guide. Study design: We used an interrupted time-series study design using generalized estimating equations to evaluate changes in prescription rate and ADE-related healthcare expenditure. Cox regression analysis was used to evaluate the probability of NSAID-associated ADEs. Methods: A total of 154,585 outpatients with musculoskeletal or connective tissue disorders, without pre-existing gastric bleeding or ulcers were included in this study. The primary outcome was the level and trend change in prescription rate, drug–drug interactions, coprescribed gastro-protective drugs, and defined daily dose (DDD) of NSAIDs. The secondary outcome was the probability of ADEs and changes in ADE-related healthcare expenditure. Results: There was a significant trend change after introducing the DUR system in terms of drug–drug interactions (−3.6%) and coprescribed gastro-protective drugs (+0.6%). The mean DDD of NSAIDs increased by 0.2. The probability of ADEs decreased overall (−1.7%) and in the high-risk group (age ≥65 years; −9.6%); however, only the latter was significant. There was no significant trend or level change in ADE-related health expenditure. Conclusions: The introduction of the DUR system was associated with more efficient prescribing, including a reduction in drug–drug interactions and an increase in the use of gastro-protective drugs. The system had a positive effect on patient outcome but was not associated with reduced ADE-related costs. Further studies are needed to evaluate the long-term effects of the DUR system in Korea.