Among 167,000 ICU Pneumonia Patients, Cannabis Misuse Was Not Independently Linked to Higher Mortality

Alcohol misuse (5.0% of patients) was associated with increased in-hospital mortality (adjusted OR 1.12, 95% CI: 1.06-1.19). Opioid misuse (1.5%) was associated with decreased mortality (OR 0.46, 95% CI: 0.39-0.53). Cannabis misuse (0.6%), stimulant misuse (0.6%), and polysubstance misuse (1.2%) showed lower mortality in unadjusted analyses but no consistent association after adjustment.

Retrospective cohort study of 167,095 ICU patients with pneumonia in the Premier Healthcare Database (2010-2017). Multivariable mixed-effects logistic regression adjusted for age, comorbidities, and hospital characteristics.

This is one of the largest studies to examine how different types of substance misuse relate to pneumonia outcomes in ICU. The finding that cannabis misuse was not independently associated with worse mortality provides some reassurance, though the study captured only diagnosed misuse disorders.

The protective association with opioid misuse is likely explained by younger age and fewer comorbidities in that group, plus possible detection bias. The lack of independent cannabis association should be interpreted cautiously given the low prevalence (0.6%) and the likelihood that cannabis use is underdiagnosed in administrative data.

Administrative data likely underdiagnose substance misuse, especially cannabis. Only 0.6% had cannabis misuse documented, far below population prevalence. Detection bias (younger, healthier patients may be more likely to have substance use documented). Cannot distinguish between active and historical use.