Adverse Consequences of Co-Occurring Opioid Use Disorder and Cannabis Use Disorder Compared to Opioid Use Disorder Only.

Background: While there is growing interest in the possibility that cannabis may be a partial substitute for opioids, studies have yet to examine whether individuals with co-occurring opioid and cannabis use disorders (OUD and CUD) have less risk of negative outcomes than those with OUD only. Objective: This study sought to compare the sociodemographic and clinical characteristics of patients diagnosed with co-occurring OUD and CUD to patients with OUD only, CUD only, and patients with any other drug use disorders. We hypothesized that co-occurring OUD and CUD would be associated with lower risk of inpatient admissions and emergency department (ED) visits, lower rates of homelessness, and fewer opioid prescriptions. Methods: Comparisons were based on bivariate analyses, logistic and linear multiple regression models of National Veterans Health Administration (VHA) data from Fiscal Year 2012. Results: Of the 234,181 (94% male) patients diagnosed with drug use disorders, 8.6% were diagnosed with co-occurring OUD and CUD; 33.3% with OUD only; 26.5% with CUD only; and 31.6% with other drug use disorders. Compared to the OUD only group (Mean = 4.8 (SD = 8.84)), the group with co-occurring OUD and CUD was associated with a lower number of opioid prescriptions (Mean = 3.79 (SD = 8.22)) (d = -0.16), but higher likelihood of inpatient psychiatric admission (RR = 1.95) and homelessness (RR = 1.52), and no significant difference in ED visits. Conclusions: These data highlight the need to further investigate whether the complex effects of cannabis use on patients with OUD are counterbalanced by potential benefits of reduced in opioid prescribing.