PHOENIX – although there was no greater risk of death from myocardial infarction or other cardiac causes or need for revascularization.
The researchers noted, however, that the study population was young, with an average age of 37.4 years, and that the study period, from 2016 to 2019, predates the legalization of recreational marijuana in a number of states.
Nonetheless, even in this young study population, marijuana users’ risk of developing peripheral artery disease (PAD) was 3.68 times greater (P < .001) than that of nonusers. PAD at a young age could precede worse outcomes later in life, the study authors said.
“Basically, marijuana users were at increased risk of being diagnosed with peripheral artery disease, but there was no increased risk for them requiring any intervention, such as a peripheral vascular intervention, nor were they at increased risk of death from what we found,” said Hirva Vyas, DO, an internal medicine resident at Hackensack University Medical Center in New Jersey, who presented the results at the Society for Cardiovascular Angiography & Interventions annual scientific sessions.
The study used data on 623,768 marijuana users from the National Inpatient Sample, a nationwide database of inpatient visits covered by all public and commercial payers, then extracted a diagnosis for PAD from all 30 million–plus patient encounters to compare PAD rates between marijuana users and nonusers. Marijuana users were more likely to be White and to have elective rather than emergency admissions (P < .001). The researchers used diagnostic codes to identify marijuana users and PAD patients.
Recreational marijuana is legal in 22 states and the District of Columbia, according to ProCon.org. Since 2019, the last year of the study, 11 states have legalized marijuana for recreational use. “It’s a data point that we studied at one point in time, only from 2016 to 2019,” Dr. Vyas said in an interview.
“As we’ve seen over the past 4-5 years, legalization has skyrocketed and recreational use has become more and more favorable not only among younger folks but older folks,” study coauthor Harsh Jain, MD, a second-year internal medicine resident at Montefiore Medical Center in New York, said in the interview. “It would be really refreshing to see how these data change as we look at endpoints from 2019 to 2023.”
Because of the young age of the study population, Dr. Jain said, these findings may not accurately represent the true cardiovascular risks of marijuana use, especially later in life.
“One of the biggest secondary endpoints that we wanted to study was the development of chronic conditions that lead to multiple rehospitalizations, the most significant one of which would be the development of heart failure,” Dr. Jain said. “However, it was difficult to stratify because, again, many of these patients were very young and so they did not carry the diagnosis for heart failure, so we couldn’t complete that subset analysis.”
The goal is to extend the study period out to 2023, Dr. Jain said. “We know that these are very crude and rudimentary data findings that we presented so far, but we’re hoping that the final paper gives us a chance to flesh out all the details of our study and also gives us a chance to expand going forward,” he said.
The findings are in line with other research into the effects of marijuana and cardiovascular disease, said Carl “Chip” Lavie, MD, medical director for cardiac rehabilitation and prevention at the John Ochsner Heart and Vascular Institute in New Orleans who’s published a number of studies on PAD and substance use, including marijuana.
“It is known that cannabis is associated with more vasoconstriction, has sympathomimetic effects, causes endothelial dysfunction and increased platelet aggregation, and is known to increase the risk of acute myocardial infarction, especially in the hour or so after use,” he said in written comments sent to this news organization.
“It is also well known to be a cause of thromboangiitis obliterans, which is in the PAD family,” he added. “Based on these mechanisms, one would expect an increased PAD and, especially, PAD events. The 3.7-fold increased risk is supportive of this increased PAD.”
One study strength, Dr. Lavie pointed out, is that it’s one of the few studies that found an association between marijuana and PAD, which hasn’t been studied as well as other cardiovascular endpoints. “However,” he said, “the limitation is this is just an inpatient sample, and it is all based on coding – e.g., a patient could have PAD and it may not have been coded.”