Regular marijuana use linked to risk for HF, major adverse heart, brain events
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Key takeaways:
- Daily marijuana users had elevated risk for incident HF compared with never users.
- Among older adults who do not use tobacco, those who use cannabis had higher risk for major CV events vs. those who do not.
PHILADELPHIA — Two observational studies presented at the American Heart Association Scientific Sessions linked regular marijuana use to elevated risk for HF and elevated risk for major adverse cardiac and cerebrovascular events.
In one study, daily marijuana users had increased risk for incident HF compared with never users, and in the other, older nonsmokers with cannabis use disorder had increased risk for major adverse cardiac and cerebrovascular events compared with older participants who did not use tobacco or cannabis.
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Marijuana and HF
For the HF study, Yakubu Bene-Alhasan, MD, MPH, a resident physician at Medstar Health in Baltimore, and colleagues analyzed data from 156,999 individuals who were free from HF when they enrolled in the NIH-sponsored All of Us Research Program to determine any association between frequency of marijuana use and incident HF.
“Marijuana use in the United States and globally has been increasing, and we expect it to continue increasing given the widespread decriminalization and public acceptance,” Bene-Alhasan told Healio. “This means physicians would encounter more and more patients using marijuana and others interested in knowing what the health effects of marijuana use is. The problem is not a lot is known regarding the health effects of marijuana use. Particularly, the cardiovascular effects are not well established, although there have studies linking its use to CAD, arrhythmias and cardiomyopathies. The AHA prompted researchers in 2020 to conduct more studies on the cardiovascular effects of marijuana use.”
Median follow-up was 45 months.
After adjustment for demographic and socioeconomic factors, diabetes, hypertension, hyperlipidemia, BMI, alcohol use and smoking status, the researchers determined that daily users of marijuana had increased risk for incident HF compared with never users (adjusted HR = 1.34; 95% CI, 1.04-1.72).
Frequency of marijuana use was not associated with risk for HF with reduced ejection fraction or HF with preserved ejection fraction. The results did not vary by age, sex at birth or tobacco smoking status.
“Marijuana use could lead to HF by first causing ischemic heart disease or arrhythmia, which eventually could lead to HF. Both ischemic heart disease and arrhythmias are established causes of HF,” Bene-Alhasan told Healio. “Previous studies have shown cannabinoid agonists bind to their receptors in the heart to reduce myocardial contraction. This has been seen in both animal and human studies. Another study also showed marijuana use leads to reduced ejection fraction and stroke index. Hence, marijuana could cause HF through reduce contractility of the heart. However, we cannot state causality from our study since it is observational.”
The relationship between frequency of marijuana use and incident HF was attenuated when CAD diagnosis was added as a time-varying covariate to the model (aHR = 1.27; 95% CI, 0.99-1.62), “suggesting CAD could be an intermediary in the pathway from marijuana use to HF,” Bene-Alhasan told Healio. “CAD is an established cause of HF and a recent study using the same database also showed daily marijuana use increases the risk of CAD. Hence, it would not be surprising if CAD is a mediator.
“We call for more researchers to evaluate the health effects of marijuana use,” he said. “That is the only way we can as physicians help patients make an inform decision on marijuana. It would also help policymakers make decisions at the state and federal level and internationally.”
Marijuana and major CV events
For the major CV event study, Avilash Mondal, MD, an internal medicine resident at Nazareth Hospital in Philadelphia, and colleagues used the NIH Inpatient Sample to identify 28,535 cannabis users aged 65 years or older with CVD risk (high BP, type 2 diabetes or high cholesterol) and no tobacco use disorder and determine risk for major adverse cardiac and cerebrovascular events. The cannabis users were compared with 10,680,280 adults aged 65 years or older with the same risk factors who did not use marijuana.
“More and more states have been approving [marijuana’s] use; however, its long-term effects are not known and not studied,” Mondal told Healio. “We need to understand its effects on the population who has been using it for a while now, hence we used an older population for this study.”
In unadjusted data, cannabis users had lower rates of all-cause mortality and dysrhythmia, higher rates of acute MI and stroke and similar rates of cardiac arrest compared with nonusers, but after adjustment for baseline demographics, hospital-level characteristics and comorbidities, cannabis users had elevated risk for major adverse cardiac or cerebrovascular events compared with nonusers (adjusted OR = 1.2; 95% CI, 1.11-1.29; P < .001).
In cannabis users, chronic lung disease, renal disease, hypertension and hyperlipidemia were predictors of major adverse cardiac and cerebrovascular events.
“We are now seeing adverse risk for cardiovascular events in patients who are using cannabis,” Mondal told Healio. “We cannot establish causality because this is an observational study. We need more research to see how cannabis use affects the microvasculature and the blood vessels.”
Reference:
- Mondal A, et al. Abstract MDP249. Presented at: American Heart Association Scientific Sessions; Nov. 11-13, 2023; Philadelphia.
Perspective
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There are concerning signals in these studies. The data would suggest that as cannabis has been legalized across the U.S. slowly and there are more people using it, there may be an underappreciation for the linkage between recreational and nonrecreational cannabis use and CVD.
An interesting aspect of these studies is their size. These are not select patient populations. The All of Us registry is run by the NIH and is collecting granular information to develop a deeper understanding of the way an individual’s environment, lifestyles and health impact outcomes, linking to factors such as genetics, which was not a part of the cannabis/HF study. The National Inpatient Sample is a limited cohort of inpatient admissions from across the United States. A highly relevant factor in both these datasets is that they are not selected to include a specific demographic but rather are more reflective of the U.S. population. A highly relevant observation in the National Inpatient Sample abstract was that it included a group of patients who probably had a higher risk for heart disease. The population in this study was older and had other premorbid conditions for heart disease. When cannabis was added on top of that, an increased risk for cardiovascular events was noted. This should not be a big surprise since the negative effects of cannabis on the CV system are well-described. A good explanation of cardiac- and vascular-specific effects of cannabis use can be found in the 2020 AHA Scientific Statement on Medical Marijuana, Recreational Cannabis and Cardiovascular Health (Page II RL, et al. Circulation. 2020;doi:10.1161/CIR.0000000000000883).
The medical community needs to be aware of this information and should be more diligent in screening patients for cannabis use and having a conversation with them about the risk implications. It is also important for the public to understand this risk. Once the use of tobacco was linked to CV and cancer outcomes, public awareness campaigns were initiated so that the population could make informed choices based on scientific knowledge. The same thing needs to happen as we begin to grow this important database around cannabis use — that the public understands the risks they are putting themselves in by utilizing cannabis products.
While there may be bias and incomplete sampling in these studies, they are large, and we need to continue developing a body of evidence to make sure that the conclusions are correct. As we continue to pull this information together, we need to be very introspective about our public policies and how we are educating the public around the risks.
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Bene-Alhasan Y, et al. Abstract MDP250. Presented at: American Heart Association Scientific Sessions; Nov. 11-13, 2023; Philadelphia.
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