Epidemiology of opioid-related visits to US Emergency Departments, 1999-2013: A retrospective study from the NHAMCS (National Hospital Ambulatory Medical Care Survey)

Abstract

Goals: To characterize the epidemiology of opioid-related visits to United States (US) emergency departments (EDs) and describe trends in opioid-related visits over time.

Design: Retrospective cohort study CASES: The National Hospital Ambulatory Care Survey (NHAMCS) was used to identify opioid-related ED visits between 1999 and 2013.

Measurements: The NHAMCS is an annual, weighted, multi-stage survey which allows for the study of ambulatory care services within a nationally representative sample of US hospitals. We used ICD-9 codes to identify ED visits related to opioid use and abuse. We applied visit weights calculated by NHAMCS to generate nation-wide estimates regarding the overall prevalence of opioid-related visits, and demographic characteristics of these patients. We report trends with respect to opioid-related visits and ED resource utilization between 1999 and 2013.

Results: 1072 visits were included, representing 2,731,000 nation-wide opioid-related ED encounters between 1999 and 2013. During this time, opioid-related ED visits increased from 125,000 in 1999 to over 300,000 visits in 2013. Between 1999-2001 and 2011-2013 opioid-related visits increased by 170%. Greater numbers of such visits occurred across nearly all demographic groups, and all regions of the US. Weighted visits among women increased by 250% between these time periods. Over these periods, opioid-related ED visits resulting in hospital admission increased by over 240%. The proportion of ED visits that were related to opioids doubled from 1999 (0.12%) to 2013 (0.25%).

Conclusions: Opioid-related ED encounters and resource utilization both rose substantially between 1999 and 2013, with consistent increases across a broad spectrum of demographic groups.

Keywords: Addiction; Emergency department; Opiates; Opioid-related disorders; Overdose.