Adverse drug event-related emergency department visits associated with complex chronic conditions.

BACKGROUND AND OBJECTIVES Outpatient adverse drug events (ADEs) can result in serious outcomes requiring emergency department (ED) visits and hospitalizations. The incidence and severity of ADEs in children with complex chronic conditions (CCCs), who often take multiple medications, is unknown. We sought to describe the characteristics of ADE-related ED visits, including association with CCC status; determine the implicated medications; and determine if CCC status increased the risk of ADE-related admission. METHODS Retrospective cohort study of ED visits by patients aged 0 to 18 years using a national sample. ADEs were identified by external cause of injury codes; cases with overdose, wrongful administration, self-harm, or diagnosis of malignancy were excluded. Multivariable logistic regression was used to test outcomes of having an ADE-related ED visit and of subsequent admission. All statistics accounted for the complex survey design. RESULTS Of 144 million ED visits, 0.5% were associated with ADEs. Adjusting for age, gender, insurance type, day of week, and location of hospital, ADEs were associated with the presence of a CCC (odds ratio 4.76; 95% confidence interval: 4.45-5.10). The implicated medications differed significantly by CCC status. Adjusting for the same variables, ADEs were associated with subsequent inpatient admission (odds ratio 2.18; 95% confidence interval: 2.04-2.32) for all children; an interaction between ADE and CCC status was not significant. CONCLUSIONS ED visits associated with ADEs were more likely to occur for children with CCCs, and the implicated drugs differed, but ADE-related admissions were not differentially affected by CCC status.