Cannabis is one of the most widely used illicit drugs in the United States. Its use has steadily increased over the last decade in part due to recreational legalization in select states. Concurrently, the prevalence of acute pancreatitis (AP) has increased, yet the etiology of many cases remains unknown. With the national trend toward increased cannabis use, we sought to determine if there was an association between cannabis use and admissions for AP after recreational cannabis was legalized.
State Inpatient Databases for Colorado and Washington were obtained before (2011) and after (2015) recreational cannabis legalization. For comparison, data from Arizona and Florida was also obtained in matching years to represent states that have not legalized recreational cannabis. These were reviewed using ICD-9 and 10 codes for acute pancreatitis, cannabis use, and other variables. Demographics (age, gender and race), comorbidities and hospital characteristics were analyzed. Multivariate comparisons were performed for AP to determine if prevalence has increased over this time period and to assess an association between AP and cannabis use. Significance was determined with a P < 0.05.
On univariate comparison, a significant increase was found for both cannabis use and admissions for AP in both legalized and non-legalized states from 2011 to 2015 (P < 0.001 for all). Multivariable adjusted analysis for AP indicated an increased odds of presentation with AP in all four states over the study period [legalized: OR 1.07 (CI 1.04, 1.10); non-legalized: OR 1.09 (CI 1.08, 1.11); P < 0.001]. However, cannabis users as a group had a lower odds of presentation with AP in Colorado [OR 0.78 (CI 0.72, 0.86); P < 0.001] and in Washington [OR 0.90 (CI 0.82, 0.98; P < 0.001].
Both cannabis use and AP increased in all states in 2015, after legalization of recreational cannabis. Interestingly, cannabis users appeared to have a decreased odds of AP in both Colorado and Washington. This suggests that although cannabis use and AP have increased from 2011 to 2015, cannabis legalization does not appear to account for the rise in AP. Further studies are needed to better clarify the role of cannabis use and other factors that have led to a rise in AP over recent years.