Frequency of Past-Year Cannabis and Other Drug Use Predicts Risk of Acute Care

The Substance Abuse and Mental Health Services Administration reports that 11.2% of the U.S. population uses cannabis or illegal drugs (2018 National Survey on Drug Use and Health). Cannabis and other drug use are associated with adverse health events, but little is known about the association between routine screening for drug use and the use of acute care services.

This retrospective cohort study, part of the CTN Primary Care Opioid Use Disorder (PROUD) Treatment Trial, used electronic health records (EHR) and claims data from 8 sites in Washington State that implemented annual substance use screening. Eligible primary care patients (N=47,447) completed screens for cannabis and/or other drug use, including illegal drug use and prescription medication misuse between March 2015 and October 2016.

Screenings assessed frequency of past-year cannabis use and other drug use: never, less than monthly, monthly, weekly, or daily/almost daily. Acute care use was measured as any urgent care, emergency department visits, or hospitalizations fewer than 19 months after screening.

Analysis found that:

• Those reporting cannabis use “less than monthly” and “daily/almost daily” had higher risk of using acute care services than patients reporting no cannabis use. However, there was no evidence of increased risk for those reporting monthly or weekly use.
• Patients reporting other drug use “less than monthly,” “weekly,” or “daily/almost daily” had greater use of acute care than those reporting no other drug use.
• Age modified several associations, with younger adults who reported cannabis use experiencing an elevated risk of acute care compared to older adults.
• Gender was also a modifier, with an increased risk of acute care observed for women, but not men.

Conclusions: In this sample of predominantly non-Hispanic white primary care patients, frequency of past-year use of cannabis and other drugs was associated with use of acute care services like emergency room visits and hospitalizations. Further research is needed to replicate these findings in more racially diverse populations, understand the conditions that lead to acute care, and evaluate whether changes in screening results are associated with changes in risk of acute care use. If replicated, these findings could have implications for counseling patients about risk associated with use of cannabis and other drugs.

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