Definition Purpose: To assist state, local, tribal, territorial, and federal public health practitioners in monitoring emergency department (ED) visits for suspected fentanyl overdoses.
New or Revised Definition: New
Date Added to ESSENCE: December 6, 2022
Definition Description: The fentanyl overdose syndrome definition was designed to be used to identify ED visits for suspected fentanyl-involved overdoses of unintentional or undetermined intent. The query uses two fields from ED visit records to identify encounters that meet the definition criteria: (1) the chief complaint free text field is queried for terms indicating an overdose/poisoning and fentanyl involvement and that don’t have any relevant exclusion terms (e.g., terms indicating fentanyl administration by medical personnel, withdrawal without acute intoxication, etc.) (2) the discharge diagnosis coded field is queried for International Classification of Diseases, 10th Revision (ICD-10-CM) and Systematized Nomenclature of Medicine (SNOMED) diagnosis codes indicating acute fentanyl poisoning of unintentional or undetermined intent.
Justification for Development: Synthetic opioids, including illicitly manufactured fentanyls, are driving recent increases in drug overdose morbidity and mortality in the United States. This definition was developed to help public health practitioners track and understand trends of nonfatal fentanyl-involved overdoses treated in EDs in near real-time.
Data Source During Development: ED visits
Development Methods: CDC scientists in the Division of Overdose Prevention (DOP) developed this definition by building off the Opioid v3 syndrome definition to capture only overdoses that indicated fentanyl involvement. First, ICD-10-CM and SNOMED diagnosis codes indicating acute fentanyl poisoning of unintentional or undetermined intent were identified. Next, overdose terms and fentanyl-specific terms that could be presented in the chief complaint free text field were identified. Lastly, exclusion terms were identified (e.g., terms indicating fentanyl administration by medical personnel, withdrawal without acute intoxication, etc.) to avoid incorrectly capturing encounters that weren’t for a fentanyl-involved overdose.
Validation Methods: CDC scientists in DOP piloted the draft definition by manually reviewing records that were captured using a broader query (e.g., any records with the word “fentanyl”) and comparing this to records that were captured using the draft definition. Multiple iterations of the draft definition were tested, and the inclusion and exclusion terms were refined with each round of review. The definition was shared with CDC National Syndromic Surveillance Program staff who reviewed the query syntax and made suggestions for improvement. The definition was further refined according to these suggestions and then shared with the 48 jurisdictions participating in CDC’s Drug Overdose Surveillance and Epidemiology (DOSE) program for review and feedback. The comment period was open for five weeks, and twelve jurisdictions submitted feedback during this period. Overall, feedback was 2 positive with minimal suggestions for revisions. The development team considered all feedback, made additional revisions, and then finalized the definition.
Definition Fields and Structure: The Chief Complaint Discharge Diagnosis (CCDD) field is used to query both the diagnosis codes and chief complaint free text with exclusions (as necessary) to develop the syndrome definition.
- Automatic inclusion:
- If a diagnosis code indicating an acute fentanyl poisoning of unintentional or undetermined intent is present, the ED visit is automatically included.
- If the chief complaint includes a fentanyl term and a naloxone term, the ED visit is automatically included.
- Conditional inclusion:
- If the ED visit does not include a diagnosis code for fentanyl poisoning or a fentanyl term and naloxone term, then the visit is not automatically included. In these instances, the visit is captured only if it includes the following two components and no exclusion terms:
- chief complaint text indicating fentanyl involvement AND
- chief complaint text indicating an overdose or poisoning
- The exclusions are applied to the chief complaint text only when the automatic inclusion criteria are not met.
- If the ED visit does not include a diagnosis code for fentanyl poisoning or a fentanyl term and naloxone term, then the visit is not automatically included. In these instances, the visit is captured only if it includes the following two components and no exclusion terms:
Limitations: The definition was developed to capture suspected fentanyl-involved overdoses treated in EDs. However, it is subject to both misclassification and underreporting for several reasons, including limited point-ofcare confirmatory testing to identify the drug(s) involved in the overdose, and reliance on self-report, bystander reports, and/or clinical presentations to determine the drug involved in an overdose. Additionally, some hospitals may enter all diagnosis codes from a patient’s entire medical history, including codes for previous fentanyl involved overdose visits; the definition may incorrectly capture such encounters that weren’t for a true fentanyl involved overdose and thus result in overreporting. Finally, fentanyl is often administered by medical personnel in the ED setting or by emergency medical services technicians en route to the ED to treat severe pain, and this information may be included in the chief complaint field. The team attempted to identify all possible exclusion terms to avoid capturing encounters that weren’t for a fentanyl-involved overdose; but, it is possible that some of these encounters were erroneously captured leading to overreporting.