Since January 2013, a nationwide drug utilization review (DUR) system for therapeutic duplication (TD) of nonsteroidal antiinflammatory drugs (NSAIDs) has been implemented in Korea. Our objective was to perform an interrupted time series study to assess changes in the pattern of NSAIDs use in knee osteoarthritis patients after implementation of the regulations.
We compared the prescribing patterns in 2012 and 2013 by means of an interrupted time series study, using the Health Insurance Review and Assessment Service database. TD was defined as use of concurrent NSAIDs either on the same or on different prescriptions for >3 days in a patient. Level change and trend change (with 95% confidence intervals [95% CIs]), and absolute and relative changes in the proportion of TDs, were estimated using segmented regression models. Multivariable logistic regression models were used to explore patient and provider characteristics associated with the TDs.
Approximately 2.5 million patients were prescribed NSAIDs in both 2012 and 2013. The proportion of TDs before and after introduction of the DUR system was 7.4% and 5.6%, respectively. Overall, an absolute reduction of 89% and a relative reduction of 30% in TDs were observed. In the postregulation period, older patients, medical aid subscribers (odds ratio [OR] 1.87 [95% CI 1.84, 1.90]), and veterans (OR 3.28 [95% CI 3.10, 3.46]) were most likely to receive NSAID TDs.
The prescription of NSAID TDs decreased with the introduction of the nationwide DUR system. Continuous adherence to the DUR regulations and safety monitoring are needed, especially with the elderly, medical aid subscribers, and veterans.