Evidence map›Paper›PMID 41468628›Full record

ArticleThe International journal on drug policy2026

What does 'polysubstance' really mean? Comparing drug-involved deaths in CDC records vs. detailed medical examiner data from Los Angeles.

Joseph R Friedman, Ruby Romero, Arthur Funnell, David Goodman-Meza, Chelsea L Shover

Abstract readComparative Study
PubMed Full text at PMC Publisher
In one paragraph

Article in The International journal on drug policy, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

What it found

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

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Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

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No citing paper in PubMed yet.

4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

5 authors.

Joseph R FriedmanDepartment of Psychiatry, University of California, San Diego, USA. Electronic address: Jofriedman@health.ucsd.edu.
Ruby RomeroDepartment of General Internal Medicine and Health Services Research, University of California, Los Angeles, USA.
Arthur FunnellClinical and Translational Science Institute, University of California, Los Angeles, USA.
David Goodman-MezaKirby Institute, University of New South Wales, Syndney, Australia.
Chelsea L ShoverDepartment of General Internal Medicine and Health Services Research, University of California, Los Angeles, USA.

Funding

A binational cohort of the intersection between substance use, HIV, and associated comorbidities among people who inject drugs in San Diego, CA U01DA063078 · NIDA · UNIVERSITY OF CALIFORNIA, SAN DIEGO · PI Britt Skaathun, Steffanie A Strathdee · 2025 to 2026
$4.9M
Predicting fatal and non-fatal overdose in Los Angeles County with Rapid Overdose Surveillance Dashboard to target street-based addiction treatment and harm reduction servicesR01DA057630 · NIDA · UNIVERSITY OF CALIFORNIA LOS ANGELES · PI David Goodman, Chelsea Leigh Shover · 2022 to 2026
$2.9M
Psychiatry Research Residency Training TrackR25MH101072 · NIMH · UNIVERSITY OF CALIFORNIA, SAN DIEGO · PI NEAL R SWERDLOW · 2013 to 2026
$2.8M
Adoption and scale-up of long-acting medications for opioid use disorder by U.S. clinicians.K01DA050771 · NIDA · UNIVERSITY OF CALIFORNIA LOS ANGELES · PI SHOVER, CHELSEA LEIGH · 2021 to 2025
$893k
NIDA NIH HHS K01 DA050771NIDA NIH HHS R01 DA057630NIDA NIH HHS U01 DA063078NIH HHS 1U01DA063078–01NIMH NIH HHS R25 MH101072
6 · The paper itself

Abstract

introductionComplex polysubstance use is increasing in the United States. However, most epidemiological literature relies on traditional data sources, especially CDC WONDER, which is limited to employing two ICD-10 codes concurrently. We leverage complete medical examiner records from Los Angeles County to examine the limitations of CDC WONDER data for detecting polysubstance drug deaths.

methodsDrug-involved deaths occurring in Los Angeles County were described using the CDC WONDER system and Los Angeles County Medical Examiner data. Annual single-drug involvement rates were compared between the two data sources. The average number of drugs, and the proportion of polysubstance deaths involving 3 or more substances was summarized by year. UpSet plot visualization was employed for complex set analysis.

resultsOverall concordance in single-substance death counts between CDC WONDER and medical examiner records was high among n = 6 substances assessed. The average number of drugs reported per death had a skewed distribution and increased from 1.72 in 2012 to 2.29 in 2023. The percentage of polysubstance deaths with 3+ drugs increased from 51% in 2012 to 74% in 2023. The number of unique polysubstance combinations with 3+ substances increased from 11 in 2012 to 57 in 2023. DISCUSSION: Although concordance is high for single-substance involvement rates, CDC WONDER fails to capture the majority of polysubstance deaths adequately, as about three-quarters of these deaths are incompletely described using its 2-drug limit. This limitation has worsened as deaths increasingly involve more drugs on average. We illustrate a huge variety of polysubstance combinations that can be seen in medical examiner deaths. As the overdose crisis grows increasingly polysubstance in nature, improving the epidemiological tracking of deaths involving multiple drugs, and drugs not captured by ICD-10 codes currently, is of paramount importance.

Indexed as

Coroners and Medical ExaminersDrug OverdoseIllicit DrugsSubstance-Related DisordersCenters for Disease Control and Prevention, U.S.HumansInternational Classification of DiseasesLos AngelesUnited StatesIllicit DrugsConcordance statisticsHealth surveillanceOverdose crisisPolysubstance

Identifiers

PMID41468628
PMCPMC12890312

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