No Detectable Association Between Frequency of Marijuana Use and Health or Healthcare Utilization Among Primary Care Patients Who Screen Positive for Drug Use

Marijuana is the most commonly used illicit drug, yet its impact on health and healthcare utilization has not been studied extensively. To assess the cross-sectional association between frequency of marijuana use and healthcare utilization (emergency department and hospitalization) and health (comorbidity, health status), we studied patients in an urban primary care clinic who reported any recent (past 3-month) drug use (marijuana, opioids, cocaine, others) on screening. Frequency of marijuana use in the past 3 months was the main independent variable [daily/ almost daily, less than daily and no use (reference group)]. Outcomes assessed were past 3-month emergency department or hospital utilization, the presence of medical comorbidity (Charlson index a parts per thousand yen 1), and health status with the EuroQol. We used separate multivariable regression models adjusting for age, sex, tobacco and other substance use. All 589 participants reported recent drug use: marijuana 84 % (29 % daily, 55 % less than daily), cocaine 25 %, opioid 23 %, other drugs 8 %; 58 % reported exclusive marijuana use. Frequency of marijuana use was not significantly associated with emergency department use {adjusted odds ratio [AOR] 0.67, [95 % confidence interval (CI) 0.36, 1.24] for daily; AOR 0.69 [95 % CI 0.40,1.18] for less than daily versus no use}, hospitalization [AOR 0.79 (95 % CI 0.35, 1.81) for daily; AOR 1.23 (95 % CI 0.63, 2.40) for less than daily versus no use], any comorbidity [AOR 0.62, (95 % CI 0.33, 1.18) for daily; AOR 0.67 (95 % CI 0.38, 1.17) for less than daily versus no use] or health status (adjusted mean EuroQol 69.1, 67.8 and 68.0 for daily, less than daily and none, respectively, global p = 0.78). Among adults in primary care who screen positive for any recent illicit or non-medical prescription drug use, we were unable to detect an association between frequency of marijuana use and health, emergency department use, or hospital utilization.