Using Emergency Medical Services Data to Monitor Nonfatal Opioid Overdoses in Real Time : Development, Validation, and Use of a Case Definition, Rhode Island, 2018.

OBJECTIVE: No case definition exists that allows public health authorities to accurately identify opioid overdoses using emergency medical services (EMS) data. We developed and evaluated a case definition for suspected nonfatal opioid overdoses in EMS data.
METHODS: To identify suspected opioid overdose-related EMS runs, in 2019 the Rhode Island Department of Health (RIDOH) developed a case definition using the primary impression, secondary impression, selection of naloxone in the dropdown field for medication given, indication of medication response in a dropdown field, and keyword search of the report narrative. We developed the case definition with input from EMS personnel and validated it using an iterative process of random medical record review. We used naloxone administration in consideration with other factors to avoid misclassification of opioid overdoses.
RESULTS: In 2018, naloxone was administered during 2513 EMS runs in Rhode Island, of which 1501 met our case definition of a nonfatal opioid overdose. Based on a review of 400 randomly selected EMS runs in which naloxone was administered, the RIDOH case definition accurately identified 90.0% of opioid overdoses and accurately excluded 83.3% of non-opioid overdose-related EMS runs. Use of the case definition enabled analyses that identified key patterns in overdose locations, people who experienced repeat overdoses, and the creation of hotspot maps to inform outbreak detection and response. PRACTICE IMPLICATIONS: EMS data can be an effective tool for monitoring overdoses in real time and informing public health practice. To accurately identify opioid overdose-related EMS runs, the use of a comprehensive case definition is essential.