Statement of Purpose In 2018, federal opioid epidemic funding doubled to $7.4 billion. National case definitions have been created to expand state-level surveillance efforts; we analyzed a CDC surveillance definition (Opioid V.1) to determine whether or not a state definition (NC DETECT) should be expanded to include additional ICD-10-CM codes and/or chief complaint keywords.

Methods/Approach Two clinically-trained independent reviewers retrospectively reviewed North Carolina (NC) ED visits to identify false positives generated by components of the Opioid V.1 definition not currently included in the NC DETECT definition. False positives were defined as any visit where available evidence, including triage notes and disposition diagnosis codes, supported an alternative explanation for patient presentation that reviewers deemed more likely than an opioid overdose. Following individual assessment, reviewers met to reconcile disagreements.

Results From 1/01/2018–7/31/2018, 2,296 ED visits were identified by Opioid V.1 but not NC DETECT criteria. Reviewers initially disagreed on 312 observations (13.6%); reconciliation led to 100% agreement. False positive rates ranged from 2.6%-41.4% for codes/keywords uniquely identifying at least 10 visits. Based on uniquely identifying 10+ visits and a false positive rate ≤10.0%, 4 of 16 (25.0%) ICD-10-CM codes evaluated were identified for NC DETECT definition inclusion. Only 2 of 25 (8%) keywords evaluated, ‘OD’ and ‘overdose’, met inclusion criteria.

Conclusions A detailed comparison of the CDC Opioid V.1 and NC DETECT opioid overdose case definitions showed significant variability in accuracy of keywords/diagnosis codes used in the federal surveillance definition.

Significance and Contributions to Injury and Violence Prevention Science The human and financial toll of the opioid epidemic produces an urgent need to ensure appropriate resource distribution to areas most in need. Findings from this analysis show the importance of this type of investigation and may prove helpful for further state or national evaluations.