Preoperative Marijuana or Opioid Use Affects Outcomes of Bariatric Surgery
Although bariatric surgery is the only known method to achieve long-term weight loss and diabetes remission, screening for opioid and marijuana use is an important part of risk stratification when considering patients for a procedure, according to several recent studies at UF Health.
W. Troy Donahoo, MD, FTOS, an associate professor in the University of Florida Division of Endocrinology, Diabetes and Metabolism, was the senior investigator in a retrospective study of 10,643 patients, age 21 years or older, who underwent bariatric surgery and were not chronic opioid users. Altogether, 4% of the patients became chronic opioid users during the first postoperative year. Intermittent opioid use before bariatric surgery doubled the risk of chronic use postoperatively, compared with no presurgical opioid use. “This indicates a need for caution when considering bariatric surgery for patients with chronic pain, especially those who already use opioids,” Donahoo says.
In a similar retrospective cohort study, 11,719 patients were assessed one year before and after bariatric surgery. Before surgery, 8% were chronic opioid users. Of those patients, 77% continued chronic opioid use after surgery, and the amount of chronic opioid use was greater postoperatively than before surgery. Furthermore, patients who were chronic opioid users prior to surgery had a significantly higher opioid requirement after surgery.
Most recently, Donahoo participated in a study of 434 patients in Colorado, where both medical and recreational use of marijuana is legal. Of those, 36 reported marijuana use before bariatric surgery. Three months after surgery there were no differences between marijuana users and nonusers in weight loss or complications, but those who reported marijuana use prior to surgery required significantly more morphine equivalents despite significantly lower ratings of their pain.
Donahoo says this study does not indicate any long-term consequences for marijuana users with regard to bariatric surgery outcomes, but because it was small and there are still many unanswered questions, caution is warranted. He notes, “Other studies of cholecystectomies in people who have used marijuana have shown similar results — that marijuana users require more opioids in the perioperative period despite having lower subjective pain scores.”
“Thinking about these three studies together, a question arises around obesity and other addictions,” Donahoo adds. “Are the changes just an addiction transfer — so that physicians need to be more aware of this risk following bariatric surgery — or is there a biological component that helps explain the results of these studies?” He explains that one of the major hormones involved in weight regulation, cortisol, is stimulated by a hypothalamic hormone that is initially made as proopiomelanocortin, a polypeptide that stimulates endogenous opioids. “These two pathways are very tightly interregulated and there may be some interesting biology there.”
Donahoo and another board-certified endocrinologist, Diana Barb, MD, physicians at UF Health Endocrinology in Gainesville – which houses a bariatric endocrinology clinic – are also diplomats of the American Board of Obesity Medicine. Their program works closely with the UF Health Bariatric Surgery Center, which is accredited as a center of excellence by the American Society for Metabolic & Bariatric Surgery.