Availability of Medical Cannabis Dispensaries and Cannabis Abuse/Dependence-Related Hospitalizations in California.

Abstract

AIMS\nTo estimate associations between both current- and prior-year medical cannabis dispensary densities and hospitalizations for cannabis use disorder in California, USA between 2013 and 2016.\n\n\nDESIGN\nSpatial analysis of ZIP code-level hospitalization discharge data using Bayesian Poisson hierarchical space-time models over 4 years.\n\n\nSETTING AND CASES\nCalifornia, USA from 2013 through 2016 (6,832 space-time ZIP code units).\n\n\nMEASUREMENTS\nWe assessed associations of annual hospitalizations for cannabis use disorder (assignment of a primary or secondary code for cannabis abuse and/or dependence using ICD-9-CM or ICD-10-CM (outcome)) with the total number of medical cannabis dispensaries per square mile in a ZIP code as well as dispensary temporal and spatial lags (primary exposures). Other exposure covariates included alcohol outlet densities, manual labor and retail sales densities, and ZIP code-level economic and demographic conditions.\n\n\nFINDINGS\nOne additional dispensary per square mile was associated with a median 2.1% increase in cannabis abuse/dependence hospitalizations in a ZIP code (95% Credible Interval 0.1-4.1% increase). Prior-year dispensary density did not appear to be associated with hospitalizations (median RR 1.006, 95% credible interval [0.986, 1.026]). Higher median household income, higher unemployment, greater off-premises alcohol outlet density, and lower on-premises alcohol outlet density and poverty were all associated with decreased ZIP code-level risk of cannabis abuse/dependence hospitalizations.\n\n\nCONCLUSIONS\nIn California USA, increasing density of medical cannabis dispensaries appears to be positively associated with same-year but not next-year hospitalizations for cannabis use disorder.