Daily cannabis users had 24% higher risk of emergency care visits in a study of 47,000 patients | Research

The takeaway

Among 47,447 primary care patients screened for substance use, daily cannabis use was associated with a 24% higher risk of subsequent acute care visits, while other drug use carried even greater risk.

Primary care physicians, health system administrators, and population health researchers.

Daily cannabis: 24% higher acute care risk; daily other drugs: 153% higher

What the researchers found

In a large prospective cohort, daily cannabis users had 24% higher risk of subsequent acute care (HR 1.24, CI 1.10-1.39) compared to non-users. Less-than-monthly cannabis use also predicted slightly higher risk (HR 1.12). Other drug use showed stronger dose-response: daily other drug use had 153% higher risk (HR 2.53).

Why it matters

This is one of the largest studies linking routine clinical cannabis screening to actual healthcare utilization outcomes. It suggests screening results have predictive value for identifying patients at risk of future acute care needs.

The numbers in context

47,447 patients; daily cannabis HR 1.24; less-than-monthly HR 1.12; daily other drug use HR 2.53; weekly other drug use HR 2.21.

How the study worked

Retrospective cohort study using EHR and claims data from 47,447 adult primary care patients across 8 Washington State sites who completed substance use screening, with up to 19 months of follow-up for acute care utilization.

What this study cannot tell us

Predominantly non-Hispanic White population (limited generalizability); single-item screening for cannabis frequency; cannot distinguish causation from correlation; Washington State may not represent other states.

How to read the evidence

Strong: large sample, prospective design, validated screening, objective outcome measures from EHR/claims data.

When this study was published

Published 2020.

The bigger picture

The finding that even infrequent cannabis use predicts slightly higher acute care risk suggests the association may not be purely dose-dependent. It could reflect broader lifestyle or risk-taking patterns associated with any cannabis use.

Questions still open

Would these associations hold in more diverse populations? Is the acute care use driven by cannabis-related events or other conditions more common among cannabis users?

Common questions

Does cannabis use predict emergency room visits?

Yes. Daily cannabis users had 24% higher risk of subsequent acute care. Even less-than-monthly users had 12% higher risk. However, other drug use carried much stronger associations.

Should doctors screen for cannabis use?

This study suggests screening results have predictive value for future healthcare utilization, supporting the utility of routine substance use screening in primary care.

Read the original research

Cannabis use, other drug use, and risk of subsequent acute care in primary care patients.

Drug and alcohol dependence, 216, 108227

View on PubMed ↗Publisher’s paper ↗

Citation

Matson, Theresa E; Lapham, Gwen T; Bobb, Jennifer F; Johnson, Eric; Richards, Julie E; Lee, Amy K; Bradley, Katharine A; Glass, Joseph E. (2020). Cannabis use, other drug use, and risk of subsequent acute care in primary care patients.. Drug and alcohol dependence, 216, 108227. https://doi.org/10.1016/j.drugalcdep.2020.108227