Cannabis use disorders and outcome of admission to intensive care: A retrospective multi-centre cohort study.

Purpose: To identify factors associated with cannabinoid use among patients admitted to ICU and its impact on survival.

Methods: A cohort of adult patients admitted to four public Australian ICUs was assembled. Individuals with mental and behavioural disorders related to cannabinoids were identified using ICD10-AM codes.

Results: Of a cohort of 34,680 admissions among 28,689 adults, 292 (0.8%) had an associated diagnosis related to cannabinoids, of which 66% were classified as harmful use, 26% as dependence syndrome/withdrawal state, 4% as psychosis/delirium, and 4% as acute intoxication. Patients with cannabinoid-use disorders were more likely to be male (73%), tended to be younger (36 vs 62 years), with fewer comorbidities and lesser severity of disease. ICU LOS was longer for those with cannabinoid-use disorders (2 vs 1 days; p < 0.0001). Patients with cannabinoid-use disorders had lower 90-day case-fatality (6% vs. 10%; p = 0.034), however no significant effect on mortality was present after adjustment for severity of illness, age, and chronic comorbidities (p = 1.0).

Conclusion: Cannabinoid-use disorders were present in 0.8% of ICU admissions in our region and were associated with increased ICU length of stay. Further studies are needed to examine cannabinoids as contributors to and modifiers of critical illness.