Using medical marijuana for chronic pain could compromise cardiovascular health

As medical marijuana use becomes more common in the US and abroad, a new study is sounding the alarm on the potential impact use of medical cannabis as a treatment for chronic pain can have on the cardiovascular health of patients.

Presented at the European Society of Cardiology (ESC) Congress 2022, the results of the study suggest use of medical cannabis for pain was associated with a 64% risk increase for arrhythmia and a 20% risk increase for acute coronary syndromes (ACS).

“Our study found that medical cannabis users had a 64% higher risk of heart rhythm disorders compared with non-users; however, the absolute risk difference was modest. It should be noted that a higher proportion of those in the cannabis group were taking other pain medications, namely non-steroidal anti-inflammatory drugs (NSAIDs), opioids and anti-epileptics, and we cannot rule out that this might explain the greater likelihood of arrhythmias,” said Nina Nouhravesh, MD, of Gentofte University Hospital, in a statement from the ESC.

Although use of marijuana, for medical purposes and recreationally, has increased in recent years, a paucity of conclusive information exists related to its effects on cardiovascular health. Citing this apparent lack of data, Nouhravesh and a team of colleagues designed the current study to estimate associations between medical cannabis use for pain and cardiovascular risk. With medical cannabis approved for use in Denmark in 2018, investigators used linked data from nationwide Danish registers to identify a cohort of patients with chronic pain and without a prior history of cardiovascular disease or medical cannabis use prior to 2018 followed until 2021.

Among the 1.6 million patients with chronic pain identified by investigators, only 4562 claimed at least 1 prescription of medical cannabis. These 4562 patients were matched to 10 nonexposed controls each based on age group, sex, and chronic pain diagnosis. The cohort of patients with exposure to medical cannabis had a median age of 58 (IQR, 47-69), was 36.7% men, 31.4% had a history of hypertension, and 42.2% reported a history of opioid use.

The primary outcome of interest for the investigators’ analyses was the 180-day standardized absolute risk (AR) and risk ratios (RR) from multivariable logistic regression models for comparing patients with and without exposure to medical cannabis. For the purpose of analysis, follow-up was initiated at the date of the first claimed prescription of medical cannabis or the corresponding date among controls. Investigators also pointed out separate analyses were planned for each chronic pain group.

Results of the investigators’ analyses indicated the risk of new­-onset arrhythmia was elevated among exposed patients with 180-day AR of 0.71% (95% CI 0.47%–0.94%) vs 0.43% (95% CI 0.37%–0.49%) yielding a RR of 1.64 (95% CI 1.04–2.23). When assessing risk of new-onset acute coronary syndrome and heart failure, results indicated the risk was not increased among those with exposure to medical cannabis compared to those without exposure, with corresponding 180­-day ARs of 0.13% (95% CI 0.03­-0.23%) vs 0.11% (95% CI 0.08-0.14%) and 0.13% (95% CI 0.03%–0.24%) vs 0.14% (95% CI 0.11%–0.17%; corresponding RRs of 1.2 [95% CI 0.3–2.1] and 0.9 [95% CI 0.2–1.7]).

“Since medical cannabis is a relatively new drug for a large market of patients with chronic pain, it is important to investigate and report serious side effects. This study indicates that there may be a previously unreported risk of arrhythmias following medical cannabis use. Even though the absolute risk difference is small, both patients and physicians should have as much information as possible when weighing up the pros and cons of any treatment.”

This study, "Cardiovascular Risk Following Cannabinoid Treatment for Patients with Chronic Pain, was presented at ESC Congress 2022.

This article originally appeared on Practical Cardiology®.