Suspected cannabinoid hyperemesis syndrome ED visits nearly tripled in Northern California over 11 years | Research

The takeaway

In a Kaiser Permanente population, suspected CHS increased 134-175% from 2009 to 2019, with over 57,000 patients experiencing at least one CHS-related emergency department visit.

People interested in cannabinoid hyperemesis syndrome trends and the health impact of increasing cannabis use.

175% increase in suspected CHS over 11 years

What the researchers found

Using a narrow CHS definition, annual prevalence increased by 175% from 2009 to 2019 (prevalence ratio=2.75). A broader definition showed a 134% increase (PR=2.34). ED visit rates also increased substantially (rate ratio=2.35 for the narrow definition). Over 57,000 patients had at least one CHS visit under the narrow definition.

Why it matters

This is one of the largest CHS prevalence studies ever conducted, using a defined health system population rather than emergency department surveillance. The near-tripling of cases over a decade tracks with increasing cannabis availability and potency in California.

The numbers in context

57,227 patients with at least 1 CHS visit (narrow definition). 65,645 (broad definition). 175% prevalence increase for narrow definition (2009-2019). 134% for broad definition. ED visit rate ratio: 2.35.

How the study worked

Retrospective observational cohort using Kaiser Permanente Northern California electronic health records (2009-2019). Two CHS case definitions applied: a narrow definition based on prior studies and a broader exploratory definition. Both required a primary vomiting diagnosis. Log-link Poisson models estimated trends.

What this study cannot tell us

ICD coding may misclassify some cases. Broader definition may capture non-CHS vomiting. CHS awareness among clinicians increased over the study period, potentially inflating diagnosis rates (detection bias). Kaiser members may not represent the general population.

How to read the evidence

Large health system database with over a decade of data and two case definitions. Robust methodology, though detection bias from increased CHS awareness may contribute to observed trends.

When this study was published

Published in 2024 covering Kaiser Permanente data from 2009-2019.

The bigger picture

CHS was considered rare when first described. This study from a large health system shows it has become a common ED diagnosis, adding urgency to the need for effective treatments and prevention strategies, particularly public education about the condition.

Questions still open

How much of the increase reflects true prevalence rise versus improved recognition? What proportion of CHS patients are chronic, recurrent users of ED services? Would public education campaigns about CHS reduce the burden?

Common questions

Is cannabinoid hyperemesis syndrome becoming more common?

Yes. This study found suspected CHS increased 175% in a large Northern California health system from 2009 to 2019, with over 57,000 patients affected. The increase tracks with expanding cannabis access and higher-potency products.

How common is CHS now?

In this Kaiser Permanente population, tens of thousands of patients had CHS-related ED visits over a decade, making it one of the most common cannabis-related conditions seen in emergency departments.

Read the original research

Prevalence and trends of suspected cannabinoid hyperemesis syndrome over an 11-year period in Northern California: An electronic health record study.

Drug and alcohol dependence, 263, 112418

View on PubMed ↗Publisher’s paper ↗

Citation

Costales, Brianna; Lu, Yun; Young-Wolff, Kelly C; Cotton, Dale M; Campbell, Cynthia I; Iturralde, Esti; Sterling, Stacy A. (2024). Prevalence and trends of suspected cannabinoid hyperemesis syndrome over an 11-year period in Northern California: An electronic health record study.. Drug and alcohol dependence, 263, 112418. https://doi.org/10.1016/j.drugalcdep.2024.112418