Weight loss surgery was associated with a small higher absolute risk of suicide or nonfatal self-harm (mainly by drug overdose) compared with nonsurgical obesity treatment, in two large matched cohorts in Sweden.
Patients both with and without a history of self-harm before the surgery were at higher risk of these outcomes, in the study published online January 9 in Lancet Diabetes & Endocrinology.
However, bariatric surgery has also been associated with increased survival in several well-designed observational studies, so "despite our finding of an increased risk of suicide, we do not believe that these results should discourage use of bariatric surgery, at least not from a survival perspective," write Martin Neovius, PhD, from the Karolinska Institute, in Stockholm, Sweden, and colleagues.
"Importantly, although the relative risk of suicide is high, the absolute risk is low," at 42 suicides over 117 000 person-years of follow-up, they stress.
Moreover, "beyond mortality, the many documented and common benefits of bariatric surgery are likely to outweigh our finding of an increased risk of suicide and self-harm."
Nevertheless, these results reinforce the importance of psychiatric assessments before and after bariatric surgery, Dr Neovius and colleagues note, and "could help to inform and refine guidelines regarding how surgery candidates are selected and followed up over time."
Similarly, in an accompanying editorial, Matthew J Spittal, PhD, from the University of Melbourne, Australia, and Gema Frühbeck, MD, from the University of Navarra, in Pamplona, Spain, caution that "these important findings should not deter patients from benefiting from the plentiful positive effects of bariatric surgery, but rather highlight the challenges it poses."
But given the increasing number of bariatric surgeries in adults and "adolescent patients, who could be an especially vulnerable group ... multidisciplinary teams treating patients need to remain aware of the constellation of pathophysiological, psychosocial, and support factors that mutually interact and potentially negatively affect a patient's postoperative course," they advise.
Absolute Differences, Particularly in Suicides, Were Small
There is growing concern about a signal of increased suicide and self-harm after bariatric surgery, but published studies have not had control groups who received nonsurgical weight-loss therapy, or have not corrected for baseline differences in mental health.
To investigate this, Dr Neovius and colleagues analyzed data from two matched cohorts of bariatric surgery patients from Sweden.
The Swedish Obese Subjects (SOS) study included some outmoded bariatric surgery procedures but had a long follow-up.
In the more recent Scandinavian Obesity Surgery Registry (SOReg)/Itrim health database study, patients underwent gastric bypass.
In the SOS study, 2010 patients who had bariatric surgery — vertical-banded gastroplasty (n = 1369), gastric banding (n = 376), and gastric bypass (n = 265) — in 1987 to 2001 were matched with 2037 patients who had usual nonsurgical obesity treatment.
During a median follow-up of 18 years, more patients in the bariatric surgery than control group were hospitalized for nonfatal self-harm or committed suicide (87 vs 49 patients; adjusted hazard ratio [HR], 1.78; P = .0021).
In the SOReg/Itrim study, 20 256 patients who had laparoscopic gastric bypass in 2006 to 2013 were matched with 16 162 patients who participated in Itrim, a commercial weight-loss program with a 3-month low-calorie diet followed by a 6-month maintenance plan (with circuit training, use of a pedometer, dietary advice, and group and individual counseling sessions).
During a mean follow-up of 3.9 years, more patients in the bariatric surgery than control group were hospitalized for nonfatal self-harm or committed suicide (341 vs 84 patients; adjusted HR, 3.16; P < .001).
"However, it is important to note that the absolute differences were small, especially for suicide (nine vs three suicides in SOS and 33 vs five in SOReg/Itrim)," Drs Spittal and Frühbeck note.
Possible Risk Factors for Suicide, Need to Carefully Select Patients
The excess risk of self-harm or suicide after bariatric surgery vs usual care or an intensive lifestyle program was not explained by insufficient weight loss, or weight regain.
However, several other possible mechanisms have been suggested, say Dr Neovius and colleagues.
For example, alcohol is metabolized by the body differently after gastric bypass surgery, so patients may get intoxicated more quickly. Micronutrient or macronutrient deficiencies that occur after bariatric surgery could also exacerbate depression or anxiety.
Bariatric surgery also causes changes in endocannabinoid signaling systems and other neuroendocrine alterations that could affect mood, anxiety, and depression, they note.
And patients may have had unrealistic expectations about changes in body shape and quality of life after surgery.
For example, "Some patients report strong dissatisfaction with their bodies after surgery because of the hanging skin folds that come from large reductions in weight," they add.
"It is important to disentangle the potential underlying mechanisms" for suicide after bariatric surgery, according to Drs Spittal and Frühbeck.
Overall, "one of the key messages to emerge from this study and others is that long-term postoperative psychological support is crucial," the editorialists stress, and it "should include clinical assessment to identify [and treat] any modifiable risk factors for suicide or self-harm."
"More can be done preoperatively, too," they stress. Clinicians need training to be able to identify psychiatric disorders, especially among vulnerable patients.
International guidelines for bariatric surgery already emphasize careful patient selection, "explicitly warning about alcohol misuse and drug dependencies, nonstabilized psychotic disorders, severe depression, and personality and eating disorders, as well as patients unable to participate in prolonged medical follow-up."
Mental health problems are generally more prevalent in patients seeking bariatric surgery.
The study was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health and Swedish Research Council. Dr Neovius has received consulting fees from Itrim. Disclosures of the other authors are listed with the article. Dr Frühbeck has participated in a Novo Nordisk obesity advisory board meeting. Dr Spittal had no relevant financial disclosures.
Lancet Diabetes Endocrinol. Published online January 9, 2018. Abstract, Editorial
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Cite this: Psychiatric Assessment Is Key Before and After Bariatric Surgery - Medscape - Jan 25, 2018.