Examination of the Accuracy of Existing Overdose Surveillance Systems

Health departments have used a variety of methods for overdose surveillance, and the Centers for Disease Control and Prevention (CDC) is implementing a standardized case definition to improve overdose surveillance nationally. The comparative accuracy of the CDC opioid overdose case definition vs existing state opioid overdose surveillance systems is unknown.

To evaluate the accuracy of the CDC opioid overdose case definition and existing Rhode Island Department of Health (RIDOH) state opioid overdose surveillance system.

This cross-sectional study of ED opioid overdose visits was conducted at 2 EDs in Providence, Rhode Island, at the state's largest health system from January to May 2021. Electronic health records (EHRs) were reviewed for opioid overdoses identified by the CDC case definition and opioid overdoses reported to the RIDOH state surveillance system. Included patients were those at study EDs whose visit met the CDC case definition, was reported to the state surveillance system, or both. True overdose cases were confirmed by EHR review using a standard case definition; 61 of 460 EHRs (13.3%) were double reviewed to estimate classification accuracy. Data were analyzed from January through May 2021.

Accurate identification of an opioid overdose was assessed by estimating the positive predictive value of the CDC case definition and state surveillance system using results from the EHR review.

Among 460 ED visits that met the CDC opioid overdose case definition, were reported to the RIDOH opioid overdose surveillance system, or both (mean [SD] age, 39.7 [13.5] years; 313 males [68.0%]; 61 Black [13.3%], 308 White [67.0%], and 91 other race [19.8%]; and 97 Hispanic or Latinx [21.1%] among each patient visit), 359 visits (78.0%) were true opioid overdoses. For these visits, the CDC case definition and RIDOH surveillance system agreed that 169 visits (36.7%) were opioid overdoses. Of 318 visits meeting the CDC opioid overdose case definition, 289 visits (90.8%; 95% CI, 87.2%-93.8%) were true opioid overdoses. Of 311 visits reported to the RIDOH surveillance system, 235 visits (75.6%; 95% CI, 70.4%-80.2%) were true opioid overdoses.

This cross-sectional study found that the CDC opioid overdose case definition more often identified true opioid overdoses compared with the Rhode Island overdose surveillance system. This finding suggests that using the CDC case definition for opioid overdose surveillance may be associated with improved data efficiency and uniformity.