Table 4.

Cyclic vomiting syndrome and cannabinoid hyperemesis syndrome diagnostic dilemmas

Author	Study design	Primary findings	GRADE rating
Kim [5]	Observational, retrospective	Following legalization of cannabis in Colorado, the prevalence of cyclic vomiting nearly doubled (prevalence ratio 1.92, 95% confidence interval [CI] = 1.33 to 2.79) and patients were more likely to have cannabis use documented (OR = 3.59, 95% CI = 1.44–9.00)	Low
Fajardo [175]	Observational, retrospective, case-control	Among 48 CVS patients, 22% of cases and 12% of controls were active or previous cannabis users (OR = 2.1, 95% CI = 0.7–6.1). Cannabis use, when present, preceded symptom onset in CVS patients.	Very low
Hejazi [187]	Observational, case-control	Among 132 CVS patients, 53% of patients deemed “non-responders” to standard therapy were chronic cannabis users	Very low
Namin [177]	Observational, cross-sectional survey	Of 31 patients diagnosed with cyclic vomiting syndrome, 72% reported hot showers as a self-therapy. Forty-two percent used cannabis daily to weekly and 2 experienced resolution of symptoms with cessation.	Very low
Oruganti [178]	Observational, cross-sectional survey	Of 20 patients diagnosed with CVS, 12 used cannabis chronically and all took hot baths/showers to alleviate symptoms.	Very low
Venkates [179]	Observational, cross-sectional survey	Among 437 CVS patients, 81% were cannabis users and 67% reported using hot showers for symptom relief. Bathing behavior was associated with cannabis use (OR 2.54, 95% confidence interval [CI] = 1.2–4.3, P = 0.0006)	Low