Development and evaluation of a standardized research definition for opioid overdose outcomes

Abstract

Background: Increasing epidemiologic and intervention research is being conducted on opioid overdose, a serious and potentially fatal outcome. However, there is little consensus on how to verify opioid overdose outcomes for research purposes. To ensure reproducibility, minimize misclassification, and permit data harmonization across studies, standardized and consistent overdose definitions are needed. The aims were to develop a case criteria classification scheme based on information commonly available in medical records and to compare it with reviewing physician clinical impression and simple encounter documentation. Methods: In 2 large health systems, we developed a case criteria classification scheme for opioid overdose based on prior literature, expert opinion, and pilot testing with sample medical records. We then identified emergency department and hospital encounters (n = 259) with at least 1 International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code representing a broad range of opioid and non-opioid related poisonings. Physicians conducted structured medical record reviews to identify the proposed case criteria and generate a clinical impression, and trained abstractors verified documentation. We then compared the case criteria classification scheme with clinical impression and encounter documentation. Results: We developed a quantitative opioid overdose case criteria classification scheme that included 3 sets of major criteria and 9 minor criteria (supporting documentation). For the encounters identified using poisoning codes, the proportion verified as opioid overdoses using the case criteria classification scheme, clinical impression, and encounter documentation ranged from 50.4% to 52.7% at one site and 55.5% to 67.2% at the second site. Discrepancies across approaches and sites related to differences in available records and documentation of clinical signs of overdose. Conclusions: We propose a novel case criteria classification scheme for opioid overdose that could be used to rigorously and consistently define overdose across multiple research settings. However, prior to widespread use, further refinement and validation are needed.

Keywords:

• Epidemiology
• heroin
• methods
• opioid analgesics
• poisoning

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Acknowledgments

We wish to thank Shane Mueller, MSW, for project coordination and data collection; Ted Palen, MD, PhD, Ruth Bedoy, and Melanie Stowell, MSc, for data collection; Kerry Broderick, MD, Jason Hoppe, DO, Joseph Frank, MD, MPH, and Andrew Monte, MD, for providing expertise and feedback on overdose definitions; and Kristin Breslin, MS, for providing data and analysis assistance.

Additional information

Funding

Funding for this study was provided by the National Institute on Drug Abuse of the National Institutes of Health under award numbers R34DA035952 and R01DA042059 and the Colorado Clinical & Translational Sciences Institute (CCTSI) with the Development and Informatics Service Center (DISC) grant support (NIH/NCRR Colorado CTSI grant number UL1 RR025780). The funding organizations had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Notes on contributors

Ingrid A. Binswanger

I.A.B. conceived of the study and design, collected data, interpreted results, and wrote the manuscript. K.J.N. assisted with research design, analysis, and revision of the manuscript. E.M.G. collected data and revised the manuscript. B.A.G. participated in conception of the study and revising the manuscript. S.C. assisted with data collection and manuscript revisions. J.M.G. conceived of the study design, interpreted results, and revised the manuscript.

Komal J. Narwaney

I.A.B. conceived of the study and design, collected data, interpreted results, and wrote the manuscript. K.J.N. assisted with research design, analysis, and revision of the manuscript. E.M.G. collected data and revised the manuscript. B.A.G. participated in conception of the study and revising the manuscript. S.C. assisted with data collection and manuscript revisions. J.M.G. conceived of the study design, interpreted results, and revised the manuscript.

Edward M. Gardner

I.A.B. conceived of the study and design, collected data, interpreted results, and wrote the manuscript. K.J.N. assisted with research design, analysis, and revision of the manuscript. E.M.G. collected data and revised the manuscript. B.A.G. participated in conception of the study and revising the manuscript. S.C. assisted with data collection and manuscript revisions. J.M.G. conceived of the study design, interpreted results, and revised the manuscript.

Barbara A. Gabella

I.A.B. conceived of the study and design, collected data, interpreted results, and wrote the manuscript. K.J.N. assisted with research design, analysis, and revision of the manuscript. E.M.G. collected data and revised the manuscript. B.A.G. participated in conception of the study and revising the manuscript. S.C. assisted with data collection and manuscript revisions. J.M.G. conceived of the study design, interpreted results, and revised the manuscript.

Susan L. Calcaterra

I.A.B. conceived of the study and design, collected data, interpreted results, and wrote the manuscript. K.J.N. assisted with research design, analysis, and revision of the manuscript. E.M.G. collected data and revised the manuscript. B.A.G. participated in conception of the study and revising the manuscript. S.C. assisted with data collection and manuscript revisions. J.M.G. conceived of the study design, interpreted results, and revised the manuscript.

Jason M. Glanz

I.A.B. conceived of the study and design, collected data, interpreted results, and wrote the manuscript. K.J.N. assisted with research design, analysis, and revision of the manuscript. E.M.G. collected data and revised the manuscript. B.A.G. participated in conception of the study and revising the manuscript. S.C. assisted with data collection and manuscript revisions. J.M.G. conceived of the study design, interpreted results, and revised the manuscript.