Cost implications of adverse drug event-related emergency department visits - a multicenter study in South Korea

Background: Adverse drug reactions (ADRs) increase health-care resource utilization, including that for emergency department (ED) visits. However, cost analyses of ADRs resulting in ED visits are scarce. Therefore, we aimed to estimate the direct medical costs before and after ADR occurrence and analyzed the cost-driving factors. Methods: The ADR cases were identified by a retrospective review of medical records of patients who visited the ED of three tertiary hospitals in South Korea from July to December 2014. The direct medical cost was estimated by the difference in costs six months before and after the ED visit. A generalized linear model was used to identify the ADR-associated cost-driving factors. Results: The mean cost per ADR increased by 26.1% (+/- SD = 4.3) during the six-month follow-up compared with that during the six months before the ED visit (p < 0.05). Preventable ADRs accounted for approximately 19.9% of the cost increase among all ADR cases. The regression analysis revealed that 'ADR-related hospitalization' was a significant (p < 0.05) factor leading to an increase in the direct medical costs. Conclusion: Drug-related ED visits increase the burden on health insurance systems and patients' out-of-pocket costs, mostly due to the hospitalization costs.