Patients undergoing Roux-en-Y gastric bypass (RYGB) surgery have an ongoing and significantly increased risk of developing alcohol-use disorder (AUD) after the procedure compared with those who have another form of bariatric surgery, laparoscopic adjustable gastric banding (LAGB), suggests a long-term cohort study.
The findings, which underline guideline recommendations for the long-term monitoring of bariatric-surgery patients, were published online March 31 in the Surgery for Obesity and Related Diseases.
The main take-home message for clinicians treating patients with a history of bariatric surgery is that “they should be screening them for AUD throughout their continued care,” according to lead author Wendy C King, PhD, associate professor, epidemiology, University of Pittsburgh Graduate School of Public Health, Pennsylvania.
“This study in particular really shows the importance of continued screening, because it wasn’t like everybody who ended up having problems had problems within the first 2 years,” she told Medscape Medical News.
“Each year, a new group patients was identified as having the onset of problems, so that indicates we really need to continue with screening long term.”
Of concern was that, although 21% of RYGB patients reported alcohol problems, less than 4% were receiving treatment for a substance-use disorder (SUD).
Dr King said in a release: “This indicates that treatment programs are underutilized by bariatric-surgery patients with alcohol problems. That’s particularly troubling given the availability of effective treatments.”
The findings are based on patients in the Longitudinal Assessment of Bariatric Surgery 2, an observational, prospective study involving 10 US hospitals in which participants were followed up annually for 7 years.
Not connected with the study, Matthew S Capehorn, MD, clinical manager, Rotherham Institute for Obesity, United Kingdom, said in an interview that the findings are “not very surprising,” although it would be a surprise to the media “because they seem to think that bariatric surgery is a magic bullet.”
The findings are “another reason why people shouldn’t be very quick to rush into bariatric surgery,” said Dr Capehorn.
“They do, regrettably, and it’s partly because of the media, I have to say; they have this impression they’ll start off super large, have the bariatric surgery, it’ll make them lose weight, and they end up super thin.
“They don’t realize that one-third do phenomenally well, one-third will only do okay, and one-third will do very badly, and there are certain occasions where the bariatric surgery just doesn’t work.”
In the current analysis, the Alcohol Use Disorders Identification Test was used to assess self-reported AUD symptoms in the past year. Participants also self-reported illicit drug use, as well as counseling and hospital admission for psychiatric or emotional problems.
The team gathered data on sociodemographic characteristic and smoking status and used the “belonging” domain score of the 12-item Interpersonal Support Evaluation List (ISEL-12) to examine perceived social support, among other measures.
Of the 2003 patients who completed baseline and follow-up assessments, 1481 underwent RYGB and 522 received LAGB. The median age of the participants was 47 years, and 79.2% were women. The median body mass index (BMI) at baseline was 45.6 kg/m2.
Patients who underwent RYGB were significantly more likely to be younger, have a higher BMI, and be unemployed than those who had LAGB and were less likely to be married, have at least a college degree, and have a higher annual income than LAGB patients.
Moreover, RYGB patients were significantly more likely to be smokers and less likely to be regular alcohol consumers, have loss-of-control eating, and have a lifetime history of psychiatric hospitalization at baseline than LAGB patients.
The researchers found, however, that the cumulative incidence of postsurgery AUD symptoms at year 5 was higher among patients who had undergone RYGB in than those who received LAGB, at 20.8% vs 11.3%.
A similar pattern was seen for illicit drug use, at a year-5 incidence of 7.5% among RYGB patients vs 4.9% for those who had LAGB; the rates were 3.5% and 0.9%, respectively, for those developing SUD.
Multivariate Cox proportional hazard models taking into account numerous potential confounding factors revealed that, compared with LAGB, RYGB was associated with an increased risk of incident AUD symptoms, at an adjusted hazard ratio (HR) of 2.08, as well as illicit drug use (HR, 1.76) and SUD treatment (HR, 3.56).
Other factors significantly and independently associated with the risk of developing AUD and illicit drug use postsurgery were male sex, younger age, smoking, and any or regular alcohol consumption before surgery.
Lower social support was also linked to an increased risk of AUD, while illicit drug use was associated with low income, antidepressant use and a history of psychiatric hospitalization. Postsurgery SUD treatment was linked to psychiatric counseling, a history of psychiatric hospitalization, smoking, and symptoms of AUD presurgery.
Intriguingly, the type of surgical procedure did not interact with any of these factors, Dr King explained, noting that, for example, younger age was related to AUD risk in both the gastric-banding and RYGB groups.
Discussing the implications of the findings for clinicians, she said the American Society for Metabolic and Bariatric Surgery recommends that patients be made aware of the risks of AUD after bariatric surgery, “and they even recommend that high-risk groups be advised to eliminate alcohol consumption, following the RYBG procedure in particular.”
However, she said that the recommendations do not “clearly define” what constitutes high-risk patients. “From our study, you might say: ‘Well, males, younger adults, and those who smoked were at higher risk.’ Are they are a higher-risk group? It’s unclear what they mean by that.”
Another area of debate is the potential mechanisms underlying the increased risk of AUD in post–bariatric-surgery patients. Pharmacokinetic and mechanistic studies have suggested that, compared with other individuals, RYGB patients have higher peak alcohol blood concentrations that are reached faster and last for longer.
One controversial theory that has received attention in the lay press is the “addiction transfer model,” in which bariatric patients have a food addiction prior to surgery that is then transferred to alcohol postsurgery, as they are no longer able to eat large amounts of food.
However, Dr King said that she and her colleagues examined both binge-eating disorder and loss-of-control eating in their study and found no association with AUD. “Although it didn’t disprove the theory, it basically gave no support for it, and there just isn’t the support for it in the literature.”
She added: “It sounds sexy to say: ‘Oh, they’re addicted to food and now they’re addicted to alcohol,’ but we have not found evidence of that.”
On the other hand, Dr Capehorn pointed to a previous paper by Müller et al, which suggested that bariatric-surgery patients may “just eat out of habit” and that “this is passed on to something else.”
“So they end up having the surgery, which affects the hormones and takes away their feeling of hunger, makes them feel full, but then it’s as though that part of the brain that controls their habituation needs to move onto something else. And, if they’ve got a sensibility for alcohol or substance use, they tend to move onto that instead,” he said.
Another potential mechanism for a link with AUD, according to Dr Capehorn, is that bariatric surgery may affect the glucagonlike peptide-1 (GLP-1) receptor pathway.
“Certainly, we know that GLP-1 analogues in the gut have an effect on the brain, so with bariatric surgeries that involve…effectively cutting out sections of the bowel that may be involved in that GLP-1 pathway, it’s not surprising that there’s a change in your brain biochemistry after those types of surgical procedures,” he said.
“Now, we don’t know the cause and effect, we don’t know the neurological pathway by which that would happen, but that’s probably a case of we just don’t know it yet because we haven’t looked; we need functional MRI scanning to figure that one out.”
This clinical study was a cooperative agreement funded by the National Institute of Diabetes and Digestive and Kidney Diseases in collaboration with Cornell University Medical Center, the University of Washington, Neuropsychiatric Research Institute, East Carolina University, University of Pittsburgh Medical Center, and Oregon Health & Science University. Dr King has received research grants from Covidien, Ethicon, Nutrisystem, and PCORI and consultant fees from Apollo Endosurgery. Disclosures for the coauthors are listed in the paper. Dr Capehorn is medical director of LighterLife, a weight-loss company.
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Surg Obes Relat Dis. Published online March 31, 2017. Abstract
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