Cannabis use and outcomes after aneurysmal subarachnoid hemorrhage: A nationwide retrospective cohort study

Background: Cannabis is the most consumed recreational drug in the world. It is possible that cannabis has an association with an increased risk of vasospasm-related strokes and delayed cerebral ischemia (DCI), which are major causes of morbidity and mortality in aneurysmal subarachnoid hemorrhage (aSAH). Hence, this study aimed to explore the independent relationship between cannabis use and outcomes after aSAH using the 2016 United States Nationwide Inpatient Sample. Methods: This study was conducted using the 2016 National Inpatient Sample with ICD-10 codes. Multivariate logistic regression was used to examine the association between cannabis use, the primary (inpatient mortality) and secondary outcomes. Results: There were 42,394 patients identified with aSAH, of whom 925 were identified as cannabis users. Cannabis users and non-users were similar in terms of severity of aSAH. Although the unadjusted mortality rate was lower among cannabis users (16%) than non-users (22%), (p = 0.04), both the age-adjusted odds ratio (OR) (0.83, 95% confidence interval (CI): 0.56; 1.24) and the multivariate-adjusted OR (0.87, 95% CI: 0.54; 1.42) did not reach statistical significance. Secondary outcomes did not reach statistical significance. Conclusion: In this nationwide cohort, cannabis users with aSAH had similar outcomes compared to nonusers. However, these results are likely limited by underreporting of cannabis use. Future prospective studies are needed to elucidate the pathophysiology and association between cannabis and outcomes following aSAH.