Only 25% of cannabis-coded ER visits were actually attributable to cannabis use

A chart review of cannabis-coded ED visits found only 25.74% were actually at least partially attributable to cannabis, with these patients being more often young, Caucasian males.

Shelton, Shelby K et al.·Clinical toxicology (Philadelphia·2020·Moderate EvidenceRetrospective Cohort
RTHC-02840Retrospective CohortModerate Evidence2020RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Retrospective Cohort
Evidence
Moderate Evidence
Sample
Not reported

What This Study Found

Of all ED visits with cannabis ICD-CM codes, detailed chart review determined only 25.74% were at least partially attributable to cannabis. These patients were more often young, Caucasian, and male compared to the overall ED population (all p values significant). The remaining ~75% had cannabis codes incidental to the visit reason.

Key Numbers

25.74% actually attributable to cannabis; patients more often young, Caucasian, male (all p<0.05); ~75% had cannabis codes incidental to visit.

How They Did This

Retrospective chart review of ED visits identified by cannabis ICD-9 and ICD-10-CM codes between 2012 and 2016, with pre-specified attribution criteria and inter-rater reliability assessment.

Why This Research Matters

Administrative data studies often use cannabis ICD codes to estimate cannabis-related ED burden. This study shows that 75% of such visits are not actually caused by cannabis, meaning published estimates of cannabis-related ED visits may be grossly inflated.

The Bigger Picture

This has major implications for cannabis policy debates. Claims about "dramatic increases in cannabis-related ER visits" based on ICD codes may be measuring coding practices rather than actual cannabis harms. Better attribution methods are needed.

What This Study Doesn't Tell Us

Single hospital system; retrospective chart review with inherent subjectivity; 2012-2016 data may not reflect current patterns; attribution criteria were pre-specified but novel; cannot determine what fraction of the 25% were primarily vs secondarily caused by cannabis.

Questions This Raises

  • ?How should cannabis-attributable ED visits be defined and measured?
  • ?Are policy claims about cannabis ED burden based on inflated administrative data?

Trust & Context

Key Stat:
Only 25.74% of cannabis-coded ED visits were actually cannabis-related
Evidence Grade:
Moderate: systematic chart review with pre-specified criteria and inter-rater reliability, but single center.
Study Age:
Published 2020.
Original Title:
Why do patients come to the emergency department after using cannabis?
Published In:
Clinical toxicology (Philadelphia, Pa.), 58(6), 453-459 (2020)
Database ID:
RTHC-02840

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-ControlFollows or compares groups over time
This study
Cross-Sectional / Observational
Case Report / Animal Study

Looks back at existing records to find patterns.

What do these levels mean? →

Frequently Asked Questions

How many ER visits are truly caused by cannabis?

This study found only about 26% of ED visits coded for cannabis were actually attributable to cannabis use. The rest had cannabis codes incidentally, meaning published statistics based on coding data may overestimate cannabis-related ER visits by about 4-fold.

Who goes to the ER for cannabis-related problems?

Among the visits truly attributable to cannabis, patients were more often young, Caucasian, and male compared to the overall ED population.

Read More on RethinkTHC

Cite This Study

RTHC-02840·https://rethinkthc.com/research/RTHC-02840

APA

Shelton, Shelby K; Mills, Eleanor; Saben, Jessica L; Devivo, Michael; Williamson, Kayla; Abbott, Diana; Hall, Katelyn E; Monte, Andrew A. (2020). Why do patients come to the emergency department after using cannabis?. Clinical toxicology (Philadelphia, Pa.), 58(6), 453-459. https://doi.org/10.1080/15563650.2019.1657582

MLA

Shelton, Shelby K, et al. "Why do patients come to the emergency department after using cannabis?." Clinical toxicology (Philadelphia, 2020. https://doi.org/10.1080/15563650.2019.1657582

RethinkTHC

RethinkTHC Research Database. "Why do patients come to the emergency department after using..." RTHC-02840. Retrieved from https://rethinkthc.com/research/shelton-2020-why-do-patients-come

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.