Considering weight loss surgery? A new tool offers a crystal ball

Having surgery to lose weight is a big step, with a big price tag, medical risks, and a potentially dramatic change in lifestyle. But it’s showing signs of becoming an increasingly effective means not only of achieving substantial weight loss, but of improving metabolic problems and, over several years, driving down heart attack and stroke risk.

But there’s a bewildering range of weight-loss surgery procedures, and as they become more common, research is showing they have different surgical risks and rates of complications. They range in cost. Some are more more likely than others to improve a patient’s diabetes, hypertension or lipids -- and thus ease the risk for heart attack and stroke. When it comes to weight loss, research has shown the procedures have different results too.

How, then, to assess which might get you the results you want?

A new tool unveiled at the annual meeting of the American Society for Metabolic and Bariatric Surgery may help patients with a body mass index over 30 -- the threshold at which obesity is diagnosed -- to navigate those complexities. Based on the accumulated experiences of 75,000 bariatric surgery patients, the Bariatric Surgery Comparison Tool details the expected outcomes of gastric banding surgery, gastric bypass surgery and sleeve gastrectomy, the three most common bariatric procedures.

Generally, patients who get gastric bypass surgery lose, on average, the greatest amount of weight in the first two years and see the most dramatic effects on obesity-related diseases following surgery, but also tend to have post-surgical complications most often. These procedures create a smaller stomach pouch and reroute food around a large part of the lower intestine, where most calories and nutrients are absorbed.

Patients who have the gastric banding procedure spend the least time recovering and have fewer complications on average. But they lose the least weight and are less likely to be able to stop taking medicine for obesity-related conditions.

Those who opt for sleeve gastrectomy, the newest of the procedures, lose a bit less weight than do those who have gastric bypass, and suffer fewer complications on average. More than half are able to discontinue medication for obesity-related disorders in the 12 months following surgery. This procedure does not move the stomach or alter the way food enters or leaves it, and thus does not reduce the absorption of nutrients from food consumed. But it does refashion the stomach into a banana-shaped tube with about 20% of its former capacity.

Devised by Ethicon Endo-Surgery Inc., a surgical device giant that makes and sells supplies used in bariatric and other surgery, the comparison tool calculates a user’s BMI and asks about age, gender, race and ethnicity, and the presence of obesity-related diseases in order to provide data that fits the user’s profile. Before speaking with a physician, a patient can use it to learn the average weight loss that can be expected with each procedure at six months, 12 months, 18 months and, in some cases, 24 months after surgery.

The tool also shows the average length of hospital stay following each procedure, and the probabilities of such risks as reoperation, hospital readmission, post-surgical illness and death.

Because there’s still not much data on bariatric procedures’ long-term effects, weight-loss estimates past the two-year mark aren’t offered. And since sleeve gastrectomy is a relatively new technique, even two-year projections aren’t yet available. But that will change early next month, when the results of 4,500 new bariatric patients -- most of them with sleeve gastrectomies -- are to be added to the database that makes individualized projections.

Dr. Elliott Fegelman, a bariatric surgeon who consulted with Ethicon in the development of the tool, said it should help patients “anticipate how they will experience a major period of weight loss” and develop realistic expectations.

The tool does not compare the cost of procedures, which can vary enormously.