Overuse of marijuana linked to surgery complications and death, study says

A man holds a joint while smoking marijuana, in Vancouver on Wednesday Oct. 17, 2018. British Columbia has released the results of its public engagement to help inform the government's decision on allowing spaces for consuming cannabis. (Darryl Dyck/The Canadian Press)

Clinical overuse of marijuana is linked to a variety of complications after major elective surgery, including blood clots, stroke, breathing difficulties, kidney issues and even death, a new study found.

“Our findings complement previous studies that have identified significant associations between cannabis use disorders and perioperative complications,” the study’s authors wrote in the report. The research team is from the department of anesthesiology, critical care and pain medicine at McGovern Medical School, part of the University of Texas Health Science Center in Houston.

Why would this be? Smoking marijuana impacts blood flow in the brain and body, decreases respiration and body temperature, contributes to airway blockages, raises blood pressure, increases heart rate, impacts heart rhythm, and more — all of which can make recovery from surgery more difficult, according to a November 2019 review of literature. Use of marijuana also increases post-op pain, according to an October 2020 study.

The new study’s finding is significant, the authors said, considering prior analyses have found nearly three of every 10 marijuana users develop a dependence on weed called cannabis use disorder.

A person is considered dependent on weed when they feel food cravings or a lack of appetite, irritability, restlessness, and mood and sleep difficulties after quitting, according to the U.S. National Institute on Drug Abuse. Marijuana use becomes an addiction when a person is unable to quit using weed even though it interferes with many aspects of life.

“People who begin using marijuana before the age of 18 are four to seven times more likely to develop a marijuana use disorder than adults,” the institute stated on its website, citing a January 2008 report.

COMMON, ELECTIVE SURGERIES

The new study, published Wednesday in the journal JAMA Surgery, analyzed data from the 2016-2019 National Inpatient Sample database on 12,422 hospitalizations after 11 types of major elective, noncardiac surgery. The surgeries included two types of hernia repair, gall bladder or colon surgery, breast lump biopsy, mastectomy or hysterectomy, hip or knee replacement, spinal fusion, and lumbar disk surgery.

Over 6,200 of the 12,422 patients had cannabis use disorder, and they were carefully matched with patients who did not, according to the study. Compared with people who were not overly dependent or addicted to marijuana, those with cannabis use disorder were more likely to suffer complications from those surgeries.

The most significant associations were for blockages of coronary arteries, stroke, injury to the kidneys, blood clots, breathing complications, infection and in-hospital death, the study found.

The difference was modest — a 7.73 per cent higher risk for those with the disorder compared with a 6.57 per cent risk for patients who didn’t have the disorder — but significant, according to the authors. People with cannabis use disorder also stayed in the hospital longer and had higher hospital bills than people without the disorder.

“In the context of increasing cannabis use rates, our findings support preoperative screening for cannabis use disorder,” the authors wrote.