Abstract Body (Do not enter title and authors here): Introduction/Background
Medical cannabis (MC) appears to have multiple effects on the cardiovascular system via sympathomimetic effects and parasympathetic effects, and there is concern that MC may potentiate major adverse cardiovascular events, such as acute myocardial infarction (AMI). However, few epidemiologic studies have evaluated cardiovascular risk associated with real-world MC use.

Research Questions/Hypothesis
Does transient MC exposure increase short-term risk for AMI?

Goals/Aims
We aimed to evaluate the association between MC and AMI risk, using a self-controlled case-time-control study design.

Methods/Approach
This case-time-control study used Medical Marijuana clinical Outcomes RepositorY (MEMORY) data, which contains OMMU Medical Marijuana Use Registry (MMUR) data linked to Medicaid claims. We included Medicaid beneficiaries with a hospitalization for AMI measured by ICD-10-CM diagnosis codes as cases. These individuals were matched 1:1 with a control (no AMI) on exact age, sex, and calendar time, where each control has at least as much follow-up time as their matched case and did not become a case themselves subsequently. Patients with medical cannabis exposure up to 30 days before AMI (or matched calendar date) were considered exposed during the hazard period, and those with exposure 90–60 days before AMI (or matched calendar date) were considered exposed during the referent period. For cases and controls, odds ratios (ORs) were calculated using multivariable conditional logistic regression by comparing MC exposure ratios between hazard period and referent period within individuals. The overall OR of the case-time-control study was estimated by dividing the OR among cases by the OR among controls.

Results
We identified 18,287 patients with an AMI (47.9% female; mean age (SD): 51.8 years old (10.3)); and 333 (0.9%) were receiving MC treatment at the time of AMI. Among cases and controls, we did not find an increase in odds of MC exposure within 30 days before AMI (case OR, 95% CI: 1.34, 0.93-1.93; control OR, 95% CI: 1.29, 0.93-1.79). Moreover, the case-time-control analysis revealed no increased in odds of MC exposure within 30 days before AMI (OR, 95% CI: 1.04, 0.64–1.71), after adjusting for background exposure trends.

Conclusion(s)
Our findings suggest that medical cannabis use was not associated with an increase in AMI risk within 30 days of use. However, more research is needed to more fully characterize risk among relevant subgroups.