Cannabis legalization in Colorado was linked to a significant increase in health care visits for vomiting, particularly in counties without prior medical cannabis markets, researchers found.
One of the most common uses for medical cannabis is treatment of chemotherapy-induced nausea and vomiting, with a synthetic cannabinoid derivative garnering FDA approval for this indication in 2018. Paradoxically, however, bouts of frequent nausea, vomiting, and abdominal pain potentially linked to cannabis use—a condition known as cannabis hyperemesis syndrome (CHS)—have become an increasing health concern.
“There is substantial concern that this increase in long-term and frequent cannabis use, especially with products containing high amounts of tetrahydrocannabinol (THC), will lead to an increase in the prevalence of CHS,” George Sam Wang, MD, Pediatric Emergency Medicine Specialist and Toxicologist at Children’s Hospital Colorado and Associate Professor of Pediatrics in the Section of Emergency Medicine, Medical Toxicology at University of Colorado Anschutz Medical Campus, and colleagues wrote in JAMA Network Open.
“As states allow medical and recreational cannabis, it is important to continue to evaluate the public health impacts of legalization,” Wang explained in an email correspondence with BreakingMED. “[Cannabis] Hyperemesis Syndrome is becoming more recognized and diagnosed and is one of those potential harms that need to be monitored.”
For their analysis, Wang and colleagues evaluated the association between cannabis legalization and vomiting-related health care visits in Colorado in order to estimate whether the opening of new cannabis markets led to an increased CHS case rate.
“Our analysis suggests that the number of vomiting-related health care encounters in Colorado has significantly increased in all counties since recreational cannabis was legalized in 2014, with a nearly 30% increase in annual cases overall,” they found. “In addition, the data indicate that, although counties with high baseline medical dispensary exposure saw large increases in terms of raw counts, counties with no previous baseline exposure experienced larger increases in both percentage and population-adjusted rates.”
These results, they added, suggest that counties with no baseline exposure to cannabis markets experience more vomiting-related health events with the opening of new recreational cannabis dispensaries, though they noted data were insufficient to directly evaluate cannabis-involved cyclical vomiting episodes.
“It would be useful for health care clinicians in states that have legalized cannabis and allow for commercial markets to know the constellation of CHS symptoms, inquire about cannabis use when appropriate, and be aware of the available treatment options,” they concluded. “Not doing so may impede physicians’ ability to meet the needs of many patients requiring emergency services and make it difficult to accurately monitor the public health association of cannabis use and legalization with a range of health measures, including cardiovascular health, pulmonary disease, injury, addiction, and behavioral health.”
In an editorial accompanying the study, Mark B. Mycyk, MD, and Joanne C. Routsolias, RN, PharmD, both of the Department of Emergency Medicine at Cook County Health in Chicago, noted that Wang et al’s finding that growth in new dispensaries was linked with increased emergency department (ED) visits for vomiting “makes sense—increasing availability of cannabis will naturally lead to increased complications. Their data are compelling and deserve thoughtful attention.”
Treating vomiting in the ED is fairly routine and in most cases easy to manage, Mycyk and Routsolias added; however, the problem is that the paradoxical cyclical vomiting caused by CHS is difficult to diagnose, “because it does not affect all users of cannabis and, when confirmed, CHS is difficult to manage.
“These cases result in frequent laboratory testing, radiographic imaging, prolonged stays, and in some cases, hospital admission when the vomiting is intractable and unresponsive to conventional therapies administered in the ED,” they continued. “Many of these patients return to the same ED or present to another ED for the same problem and often undergo repeated and redundant testing. The severity of vomiting in CHS makes clinicians and nurses uncomfortable: their uncertainty that something other than cannabis is the underlying cause naturally leads to additional expensive diagnostic testing. Emergency departments are already stretched with increasing volumes and frequent boarding. Any increase in ED cases for vomiting affects the time to treatment and level of attention received by patients seeking ED care not related to a cannabis problem.”
For their cross-sectional analysis, Wang and colleagues pulled data from a pair of statewide administrative data sources in Colorado; cannabis dispensary data were obtained from the Colorado Department of Revenue Marijuana Enforcement Division, and data on all ED claims involving vomiting reported to the Colorado Hospital Association from Jan. 1, 2013, and Dec. 31, 2018, were linked to dispensary locations using patient’s zip codes.
Colorado counties were categorized according to size of medical cannabis markets prior to recreational cannabis legalization: no market (no licensed dispensaries), low market (1-9 dispensaries), and high market (≥10 dispensaries). The study’s primary outcome was county per capita rate of vomiting-related ED claims per quarter.
“Vomiting-related ED health care encounters increased from 119,312 in 2013 to 153,699 in 2018 (29% increase). Over this period, 203,861 patients (25%) were aged 0 to 18 years; 114,201 (14%) were aged 19 to 25 years, and 502,771 (61%) were aged 26 years or older; 510,584 patients (62%) were female,” Wang and colleagues wrote. “Additional recreational dispensaries were associated with increased vomiting-related ED visits (incidence rate ratio, 1.03; 95% CI, 1.01-1.05), but counties with high baseline medical dispensary exposure experienced smaller increases in vomiting-related ED visits than counties with no baseline medical dispensary exposure (incidence rate ratio, 0.97; 95% CI, 0.95-0.99). Counties with a high number of medical marijuana dispensaries had increases at a 5.8% slower rate than counties with none.”
Wang told BreakingMED that, given the evidence that CHS is more common among habitual cannabis users, there findings were not particularly surprising. However, he did note that “there is more research that needs to be done on who is more susceptible to having these symptoms, treatment, and what cannabis products or potency seems to be more associated with CHS.” For example, while low-level THC has antiemetic properties, it is theorized that higher THC levels can induce vomiting.
As for how best to coordinate treatment, Mycyk and Routsolias pointed to evidence-based guidelines passed by the County of San Diego Health and Human Services Agency and San Diego Kaiser Permanente Division of Medical Toxicology “in anticipation of seeing a larger number of vomiting cases associated with cannabis use. Their goals were to raise awareness and standardize treatment: that type of approach, using the expertise of different agencies to collaborate with the goal of optimizing patient care and available resources, may be useful in Colorado and other states where cannabis use is now legal.”
The editorialists added that the conclusion by Wang et al “that growth in new recreational cannabis markets is associated with increased ED visits for vomiting will undoubtedly be confirmed by future rigorous studies in other states and it will not be surprising if we observe similar increases in ED visits for other adverse effects associated with increased cannabis availability.” They pointed to increases in ED mental health visits and increased calls to poison centers linked to cannabis, as well as increased rates of pediatric morbidities from unintentional ingestion of edible cannabis products.
“The huge tax revenue benefitting states that have legalized cannabis is obvious, but how that revenue is used deserves constructive debate by all stakeholders,” they wrote. “It is necessary to apply a data-based approach to examine the financial and resource burden on the entire health care system from vomiting and other unintended consequences of legalizing cannabis.”
Study limitations include an inability to account for unlicensed dispensaries and that the analysis may underestimate the total association between the cannabis market openind and the need for ED services.
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Cannabis legalization in Colorado was linked to a significant increase in health care visits for vomiting, or cannabis hyperemesis syndrome (CHS), particularly in counties without prior medical cannabis markets.
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More research is needed to determine who is more susceptible to having these symptoms, how best to treat CHS, and what cannabis products or potency seems to be more associated with CHS.
John McKenna, Associate Editor, BreakingMED™
Wang reported receiving royalties from UpToDate for authorship contributions on related topics. Coauthor Pacula reported nondesignated research support funds from the University of Southern California during the conduct of the study and grants from the Centers for Disease Control & Prevention and National Institutes of Health outside the submitted work.
Mycyk and Routsolias had no relevant relationships to disclose.
Cat ID: 254
Topic ID: 253,254,254,730,192,144,146,151,925
