Opioid-involved Emergency Department Visits in the National Hospital Care Survey and the National Hospital Ambulatory Medical Care Survey.

Purpose-This report compares 2014 National Hospital Care Survey (NHCS) emergency department (ED) data with national estimates of ED visits due to opioid use (i.e., "opioid-involved visits") from the 2013-2015 National Hospital Ambulatory Medical Care Survey (NHAMCS) to determine the potential of researching the impact and outcomes of opioid use on hospital EDs with non-nationally representative NHCS data. The 2014 NHCS data are also linked to records in the 2014 and 2015 National Death Index (NDI) to examine mortality after the opioid-involved ED visit. Methods-A previously published algorithm, which uses a list of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes and external-cause-of-injury codes denoting opioid use, was used to identify opioid-involved visits in NHCS and NHAMCS, which are compared by sex and age. Weighted percentage estimates and their 95% confidence intervals (CIs) are shown for all demographic characteristics using NHAMCS data. Unweighted percentages are presented for all demographic and health care characteristics using NHCS data. Standard errors and CIs are also presented for the NHCS unweighted percentages as a measure of variability. Results-The percentage of opioid-involved ED visits from NHCS fell within measures of statistical variation from NHAMCS by sex and several age groups. Less consistency of NHCS results compared with NHAMCS was seen for sex-specific age groups. NHCS has a higher percentage of opioid-involved ED visits and a higher percentage of opioid-involved ED visits for those aged 25-34, but a lower percentage for those aged 25 and under. NHCS data show that 19.2% of patients with any opioid-involved ED visit made two or more such visits, and 1.2% died within 30 days post-discharge.