The effects of Drug Utilization Review system on patient care: Changes in prescription patterns, adverse drug events and related costs

Abstract

Background: Medical errors and health care quality have been considered important issues for healthcare providers, policymakers, patients and other stakeholders. Of these errors, drug issues were the most common single-type adverse event. Drug utilization requires careful consideration, taking into account benefits and risks, and should only be used to improve the health condition if the benefits are judged to be beyond the risk of harm. If the chosen medication is not appropriate for patient treatment, it can lead to overuse/misapplication, which is the cause of most medical errors. Therefore, system-based decision support programs are considered to be an important method to improve the quality of patient care. In Korea, a systembased approach to reduce inappropriate prescription of medication began to be provided, in realtime, starting in December 2010. The purpose of this study was to evaluate the effects of the Drug Utilization Review (DUR) system in changing prescription patterns, patient adverse drug events (ADEs), and costs related to ADEs.

Materials and Methods: Data used in this study were derived from the National Health Insurance Service national sampling cohort data from 2002 to 2013, and 853,676 patients who were prescribed a drug with high ADE potential were included. To assess the effects of the DUR system on changes in prescription patterns and ADEs, this study considered several outcome variables, including prescription rate, (drug-drug interactions [DDIs], drug overdoses, specific drugs related with ADEs) and ADEs (rate, episode-based costs). In particular, drug overdoses were categorized into enrolled lists and latest lists, depending on whether they were enrolled in II the DUR system by 2013. To evaluate changes in outcome variables after introduction of DUR system, this study used an interrupted time series study design, using Generalized Estimating Equations. A Poisson distribution, with a log link function, was utilized to evaluate change in prescription and ADE patterns. Additionally, cost change was evaluated using a gamma distribution with log link function.

Results: The mean monthly prescription rate of DDI was 0.06% prior to intervention. This rate was significantly decreased to 0.03% after intervention (p < 0.0001). There was also a significant difference in the rate of drug overdoses, before and after introduction of DUR system, in both enrolled lists and latest lists. The average monthly rate of ADEs was 2.95% before intervention and 3.79% after intervention (p < 0.0001). The episode based costs related to ADEs were 107,419 KRW before intervention, and 97,342 KRW after introduction of the DUR system (p = 0.0110). The interrupted analysis showed that monthly prescription rates changed after the introduction of the DUR system. The rate of DDIs immediately decreased to 23.2% (p = 0.0084), and trends were also decreased to 1.6% (p < 0.0001), compared with pre-intervention periods. Regarding the rate of drug overdose, there has been a significant level and trend change of –14.28% (p < 0.0001) and –0.46% (p < 0.0001) respectively, in the enrolled lists. By the latest lists of existing-registered drugs, there was a significant decrease at the moment of intervention (–47.64%, p < 0.0001), as well as a trend change (–0.46%, p < 0.0001) compared to the period prior to intervention. According to the introduction of the DUR system, an immediate reduction of 1.89% (p < 0.0001) in overall ADE rates and a 1.13% (p = 0.0005) reduction in monthly rates were observed. However, this study did not found a significant level and trend change in episode-based ADE costs.

Discussion and Conclusion: Physicians' initial drug choices are influenced by several factors, including features of patients and physicians. Additionally, this decision is also affected by a III system that takes into account patient characteristics, which can lead to changes in the prescription of the drug. Changes in the prescription to reduce inappropriate drugs or reduce potential ADEs can ultimately affect the patient, leading to better results, and/or reducing the incidence of side effects. The results of this study provide policy makers with evidence that a system-based approach to quality improvement not only reduces inappropriate prescriptions, but is also an effective way to reduce side effects associated with drug use. This information can provide a basis for policy makers to reach better conclusions when choosing one of the various ways to improve quality. Through such a system-based approach, this study expected to improve patient safety and reduce medical errors.