How Safe is Bariatric Surgery?

Jacob A. Greenberg; Malcolm K. Robinson



The use of bariatric surgery for the treatment of morbid obesity has increased dramatically over the past decade, which has raised concerns about safety, efficacy and cost-effectiveness. A new study by the Longitudinal Assessment of Bariatric Surgery consortium has assessed the safety of these increasingly frequent procedures.


Clinicians are still struggling to find a solution to the world's growing weight problem. New diets, prescriptions pills and exercise videos become available every week. Unfortunately, however, these weight-loss strategies fail to produce substantial, durable weight reduction for the vast majority of patients with morbid obesity. As a consequence, patients and physicians have turned to a more drastic approach to weight loss: bariatric surgery. Despite the 10-fold rise in bariatric procedures in the US—from 16,200 surgeries in 1994 to 171,000 procedures in 2005—the safety and advisability of such an extremely invasive therapy is often questioned. The Longitudinal Assessment of Bariatric Surgery (LABS) consortium have published the results of their first study, LABS-1, in the New England Journal of Medicine, which indicate that the overall risk of adverse outcomes of bariatric surgical procedures is low and contingent on patient characteristics.[1]

LABS-1 was a prospective, multicenter, observational study, which measured the 30-day morbidity and mortality of 4,776 patients who underwent one of the three most frequent bariatric surgical procedures performed in the US. The investigators found an overall mortality rate of 0.3% and a major complication rate of 4.1%, both of which are comparable to other major abdominal surgical procedures. Furthermore, they noted that patients with obstructive sleep apnea, poor functional status (for example, the inability to walk more than 100 feet), or a history of prior thrombotic events had increased complication rates.

The procedures evaluated in this study included open and laparoscopic Roux-en-Y gastric bypass, and laparoscopic adjustable gastric banding. Roux-en-Y gastric bypass involves the creation of a small upper stomach pouch and its attachment to the jejunum, which results in bypass of the rest of the stomach and the duodenum. This bypass leads to weight loss by restriction of food intake, as well as through a variety of poorly understood neurohormonal changes that enhance satiety. During the procedure of laparoscopic gastric banding, a small stomach pouch is generated by placement of an adjustable band around the upper stomach. Weight loss predominantly occurs as a result of restricted food intake, although neurohormonal changes that enhance satiety can also occur with this procedure. The LABS-1 investigators found that the 30-day composite end point of death, major thrombotic complication, reintervention and prolonged hospitalization was 1.0% for laparoscopic adjustable gastric banding, 4.8% for laparoscopic Roux-en-Y gastric bypass surgery, and 7.8% for open Roux-en-Y gastric bypass surgery.


Laproscopic adjustable gastric banding and Roux-en-Y gastic bypass

The literature is rife with data on both the short-term and the long-term outcomes of bariatric surgery; however, the LABS-1 study differs from previous studies in a variety of ways. Previous data on clinical outcomes of bariatric surgery cannot be generalized, as they are derived from retrospective studies published by individual surgeons or institutions.[2,3] Inclusion of data from centers that do not practice state-of-the-art care within a comprehensive bariatric program might have added to the perception of increased adverse outcomes after bariatric surgery compared with other abdominal surgical procedures.

By contrast, the LABS-1 researchers analyzed data from patients treated by 33 different surgeons at 10 different clinical sites. Pertinent data points such as the primary endpoint and the presence or absence of specific prior comorbidities, were clearly defined and the data were managed by trained data collectors. Some critics might argue that the LABS-1 data underestimates the true morbidity and mortality of bariatric surgery, as the procedures analyzed were performed by highly skilled surgeons at high-volume centers of excellence which perform more than 100 laparoscopic Roux-en-y gastric bypasses annually. Previous research, however, has revealed that outcomes of both high-volume and low-volume programs are similar between centers of excellence and centers without said designation.[4] The data analyzed in LABS-1, therefore, represents the current state of the art in bariatric surgery and the study provides both surgeons and patients with realistic expectations of postoperative safety of three different bariatric procedures.

What LABS-1 does not address is the efficacy of bariatric surgery. Clinicians must be careful not to recommend a type of bariatric surgery on the basis of safety data alone. For example, although laparoscopic adjustable gastric banding is currently considered the safest bariatric procedure, gastric bypass might be the best option for patients who require substantial and durable weight loss.[5] In addition, bariatric procedures vary not only in the time until weight loss is achieved or the mechanisms that effect weight reduction, but also in their effects on glycemic control. After placement of an adjustable gastric band, improvements in glycemic control are dependent on weight loss, and patients might not see appreciable improvements in blood glucose control for some time.[6] After Roux-en-Y gastric bypass, most patients see an improvement in their glycemic control before any weight loss occurs. Although the mechanisms behind these changes are complex and not entirely clear, an alteration in the release of gut peptides seems to improve glycemic control independent of weight loss.[7] These effects, coupled with safety and other factors, must all be taken into account when a bariatric procedure is recommended for an individual patient. The results of the long-term LABS-2 study, currently in progress, will hopefully shed light on these efficacy issues and treatment recommendations.

In light of the imminent health-care reform proposed by the Obama administration, questions of cost-effectiveness must be addressed for all treatments, and bariatric surgery is no exception. The long-term health benefits after bariatric surgery include improved cardiovascular-related and diabetes-related outcomes. These improvements in comorbidities are associated with a decrease in mortality that ranges from 24-40% compared to patients treated non-surgically, as indicated by two other important studies published in the New England Journal of Medicine.[2,5] Ameliorations in overall health can lead to compensatory decreases in cost, if patients require fewer medications and less frequent hospitalizations than previously. At this point, however, it remains to be determined whether these decreases in cost are equivalent to the upfront cost of surgery and perioperative care. Further research through long-term cost-benefit analyses is needed before these questions can be answered adequately.

The prevalence of obesity and obesity-related disorders is on the rise in young adults, adolescents, and even in the pediatric population. Hence, this problem is unlikely to be resolved in the near future. In a perfect world, primary prevention through diet and exercise would alleviate the need for any surgical intervention. Unfortunately, until we begin to see success with primary prevention or develop equally effective medical management, bariatric surgery will remain an important—and reasonably safe—tool in our armamentarium for the treatment of obesity.


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