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

Background

As access to cannabis has increased, there has been a rise in a condition called cannabinoid hyperemesis syndrome (CHS). This study estimates annual prevalence of suspected CHS at emergency department visits (ED) over an 11-year period in Northern California.

Methods

This retrospective observational cohort study used electronic health records from Kaiser Permanente Northern California. Two CHS case definitions were used to construct two cohorts of adults (18+) with ≥1 CHS visits from 2009 to 2019. The primary definition used a narrow definition based on past studies (CHS group 1) and an exploratory definition allowed for a broader range of codes (CHS group 2); both definitions required a primary diagnosis of vomiting. Annual prevalence of CHS and annual rates of counts of CHS visits estimated using a log-link Poisson model are reported per group.

Findings

There were 57,227 patients with ≥1 CHS visits included in CHS group 1 and 65,645 patients included in CHS group 2. Over eleven years, CHS increased across groups with the fastest rise in CHS group 1 (prevalence ratio = 2.75, 95 % confidence interval [CI] 2.65–2.85, p<.0001 from 2009 to 2019 vs. prevalence ratio = 2.34, 95 % CI 2.27–2.43). CHS group 1 also exhibited the largest increase in ED visits (rate ratio = 2.35, 95 % CI 2.27–2.43, p<.0001).

Conclusion

In a large California population, suspected CHS increased over time across definitions. Annual prevalence increased by 134–175 %, depending on CHS definition. CHS group 2’s definition may have been too broad and changes in ICD-10-CM coding may have impacted estimates.