By George Ochoa
The prevalence of alcohol use disorder (AUD) increases in the second year after bariatric surgery compared with the year prior to surgery and postoperative year 1 (POY 1), according to a study in JAMA (2012;307:2516-2525). The association is particularly strong for patients who underwent a Roux-en-Y gastric bypass (RYGB). The large, prospective study confirmed previous retrospective reports suggesting that gastric bypass might increase AUD.
“Although there have been anecdotal reports of alcohol-related problems after bariatric surgery and pharmacokinetic studies that have shown that patients experience alcohol differently after Roux-en-Y gastric bypass, there has not been good empirical evidence that the risk for AUD increases after bariatric surgery,” lead author Wendy C. King, PhD, assistant professor, Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, said in an interview.
Dr. King and her colleagues conducted a prospective cohort study of adults undergoing bariatric surgery at 10 hospitals in the United States. Of 2,458 patients, 1,945 completed pre- and postoperative assessments. The main outcome measure was
past-year AUD symptoms as determined with the Alcohol Use Disorders Identification Test, a 10-item instrument for assessing alcohol use and alcohol-related consequences in the prior 12 months.
Although there was no significant difference in prevalence of AUD symptoms between one year prior to surgery and one year after (7.6% vs. 7.3%; P=0.98), prevalence of AUD symptoms in POY 2 was significantly higher (9.6%; P=0.01). Undergoing RYGB was independently associated with an increased likelihood of AUD after surgery. Other variables independently related to higher likelihood of postoperative AUD were preoperative AUD, regular alcohol consumption, recreational drug use, male sex and younger age.
There are a number of reasons why AUD prevalence might increase after gastric bypass. “When patients lose weight, they become more social,” said John Morton, MD, MPH, FACS, FASMBS, associate professor, section chief, Minimally Invasive Surgery, and director, Bariatric Surgery & Surgical Quality, Stanford School of Medicine, Stanford, Calif., who was not associated with the study. “They may fall into bad habits, and start drinking because they’re thinner. … There are [also] physiologic issues.”
Dr. Morton also noted that patients might have more difficultly processing alcohol after RYGB. In a study Dr. Morton conducted, patients exhibited a higher peak breath alcohol content after drinking and required more time to become sober post-RYGB (J Am Coll Surg 2011;212:209-214). A possible explanation is that after gastric RYGB surgery, alcohol bypasses the stomach and enters the bloodstream from the small intestine, which is “very absorptive,” said Dr. Morton.
The reason AUD prevalence did not increase until POY 2 may be that patients who underwent RYGB reduced alcohol consumption in POY 1 and, in POY 2, resumed drinking at preoperative levels. “Thus the increase in AUD seen in the second year may have resulted from an increase in alcohol sensitivity following the surgery coupled with the resumption of preoperative drinking levels,” she commented. “However, our study did not assess why patients drank more the second year.”
Dr. Morton said the study’s major limitation is generalizability. “It’s not an enormous number of centers. The results might have been mitigated at other centers where there was better counseling.”
He added, “I think the study is valuable, if only for the education it offers. … We should call on gastric surgeons to educate patients about the potential for alcohol misuse. I would caution about rejecting bariatric surgery. The benefits of gastric bypass outweigh the drawbacks.”
Dr. King also stressed the need for education. “Given our findings, as well as the findings from pharmacokinetic studies, patients should be educated about the potential of at least some bariatric surgical procedures, such as the Roux-en-Y gastric bypass, to increase the risk of problem-related drinking.”
Drs. King and Morton reported no relevant financial conflicts of interest.