Introduction:
Cannabis is increasingly becoming a socially acceptable substance with multiple countries having legalized its consumption. Epidemiological studies have demonstrated an association between cannabis use and an increased risk of developing coronary artery disease. However, there is a lack of studies about the influence of cannabis consumption on the outcomes following acute myocardial infarction (AMI).

Material and methods:
We retrospectively analyzed hospitalized patients with a primary diagnosis of AMI from the 2001 to 2020 National Inpatient Sample (NIS). Pearson’s Chi-Square tests were applied to categorical variables, and T-tests for continuous variables. We conducted a 1:1 propensity score matching (PSM). Multivariate regression models were deployed on the PSM sample to estimate the differences in several events and all-cause mortality.

Results:
A total of 9930007 AMI patients were studied, of whom 117641 (1.2%) reported cannabis use. Cannabis users had lower odds of atrial fibrillation (aOR 0.902, p<0.01), ventricular fibrillation (aOR 0.919, p<0.01), cardiogenic shock (aOR 0.730, p<0.01), acute ischemic stroke (aOR 0.825, p<0.01), cardiac arrest (aOR 0.936, p=0.010), undergoing PCI (aOR 0.826, p<0.01), using IABP (aOR 0.835, p<0.01) and all-cause mortality (aOR 0.640, p<0.01), with higher odds of supraventricular tachycardia (aOR 1.104, p<0.01), ventricular tachycardia (aOR 1.054, p<0.01), CABG use (aOR 1.040, p=0.010), and acute kidney injury (aOR 1.103, p<0.01).

Conclusions:
Among patients aged 18–80 years admitted to hospital with AMI between 2001 and 2020 in the United States, cannabis use was associated with lower risks of cardiogenic shock, acute ischemic stroke, cardiac arrest, PCI use, and in-hospital mortality.