Rare surgery brings more weight loss, more risks

NEW YORK Tue Sep 6, 2011 3:45pm EDT

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NEW YORK (Reuters Health) - A less common form of obesity surgery may spur more weight loss than its far more popular cousin, gastric bypass -- but at the price of greater long-term risks, researchers reported Tuesday.

The study, published in the Annals of Internal Medicine, followed 60 severely obese patients who were randomly assigned to either gastric bypass surgery or a more extensive procedure known as duodenal switch.

Two years after surgery, duodenal switch patients had lost more weight: about 50 pounds more, on average.

People shed a substantial amount of weight with either type of surgery. Gastric bypass patients cut an average of 111 pounds, while duodenal switch patients dropped about 162.

But those extra pounds came with nearly double the complication rate.

Of the 29 duodenal switch patients, 62 percent had problems like abdominal pain, vomiting, diarrhea and intestinal obstruction. And several suffered long-term malnutrition -- something not seen in the gastric bypass group.

Duodenal switch is not a popular procedure. In a 2008 study, it accounted for just 1 percent of weight-loss, or bariatric, surgeries done in the U.S., and 5 percent in Europe.

The technique is often reserved for "superobese" patients with a body mass index (BMI) of 50 or higher -- though some surgeons perform it with less severely obese patients too, explained Dr. Torgeir T. Sovik of Oslo University in Norway, the lead researcher on the new study.

"As duodenal switch can be associated with more adverse events, this procedure should only be performed in carefully selected patients by a dedicated bariatric team," Sovik told Reuters Health in an email. "And a closer follow-up after surgery is required after such procedures."

But an expert not involved in the study went further.

"This is an operation that should probably go away," said Dr. Edward H. Livingston, a professor and surgeon at the University of Texas Southwestern Medical Center in Dallas.

The average weight loss seen with either gastric bypass or duodenal switch will improve or reverse obesity-related ills like diabetes, sleep apnea and knee arthritis, according to Livingston, who wrote an editorial published with the study.

So for those medical conditions, it probably wouldn't matter if a person lost 100 pounds or 150 pounds over two years.

BMI is a measure of weight relative to height. A BMI between 18.5 and 24.9 is considered normal weight, and above 30 is obese.

The patients in the current study were a fairly healthy group despite having a BMI of 50 or more.

After two years, those who'd had a duodenal switch showed a greater improvement in their cholesterol levels. But those levels were near-normal (in both groups) to begin with, Livingston noted.

That begs the question, he said, of whether the extra weight loss "actually accomplished anything."

"The answer is 'no,'" Livingston said.

In the U.S., where about 220,000 people underwent weight-loss surgery in 2009, gastric bypass is the most common form chosen.

During gastric bypass, the upper portion of the stomach is stapled off to create a smaller pouch that restricts the amount of food a person can eat at one time. The surgeon also creates a bypass around the rest of the stomach and a portion of the small intestine, which limits the body's absorption of food.

Duodenal switch is more extensive. The surgeon removes part of the stomach, and the remaining "sleeve"-like stomach is attached to the final section of the small intestine; that puts even greater limits on the body's absorption of calories and nutrients.

Both surgeries carry the long-term risk of nutritional deficiencies, and people need to take supplements and carefully monitor their diets for a lifetime afterward.

But the risks of nutrient deficiencies are greater with duodenal switch, and include some not seen with gastric bypass, Livingston pointed out.

Some people, for instance, may have severe calcium and vitamin D loss leading to weak and fragile bones. Other problems include severe protein deficiency and night blindness caused by vitamin A deficiency (which is also reversible with extra vitamin A treatment).

In this study, three of the 29 duodenal switch patients developed protein malnutrition, two developed night blindness, and one had a severe iron deficiency that needed to be treated with iron infusions.

Livingston said his advice to people considering weight-loss surgery is to avoid duodenal switch. "It's just not a good operation," he asserted.

But he also questioned the value of weight-loss surgery, in general, for severely obese people who do not have medical conditions that stand to improve or resolve after surgery.

In general, experts say that surgery could be an option for anyone with a BMI of 40 or higher; that translates, roughly, to a man who is at least 100 pounds overweight or a woman who is 80 pounds overweight.

Livingston said he thinks more caution is in order when a very obese person is otherwise healthy.

Along with the risks of surgery, he said, there is still uncertainty about whether it actually lengthens people's lives. Some studies have suggested it might, but not all.

In a study recently published in the Journal of the American Medical Association, Livingston and his colleagues found no survival advantage among severely obese patients who'd undergone weight-loss surgery versus those who hadn't.

The study involved 850 U.S. veterans who underwent some form of weight-loss surgery, at an average age of about 50, and more than 41,000 vets who had only non-surgical care. There was no evidence that surgery improved longevity over the next seven years.

"We really don't even know if there's a survival benefit," Livingston said.

That, he added, makes the risks of duodenal switch seem even less worthwhile.

But according to Sovik, duodenal switch might be appropriate for some superobese patients.

In the U.S., he said, about one in three weight-loss surgery candidates have a BMI of 50 or higher. And studies suggest that a sizable percentage of those people will still have a BMI higher than 40 after gastric bypass.

In this study, one-quarter of gastric bypass patients still had a BMI that high two years after surgery -- versus none of the duodenal switch patients.

More extensive monitoring after duodenal switch, Sovik noted, can help detect and manage side effects.

He pointed out, though, that larger, longer-term studies are still needed to show whether the extra weight loss with duodenal switch ultimately improves severely obese patients' health and extends their lives.

SOURCE: bit.ly/mQAUrf Annals of Internal Medicine, online September 6, 2011.

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Comments (3)
GirlPower wrote:
See, the thing is, the thing that they’re failing to mention in this article, is that duodenal switch patients need to be properly educated by their surgeons. Because of this many duodenal switch patients probably do have malnutrition and vitamin deficiencies. If a DS patient is advisd to consume twice the protein of a RNY patient the DS patient will not suffer protein deficiencies. If they are taught to take the correct amount and dosages of vitamins and supplements it is unlikely they will suffer malnutrition. It’s sort of like wondering why a third grader can’t spell when his teachers don’t teach him how. DS is not as complicated, or as dangerous, as this article will have you believe… IF the surgeon and his team properly educate their patients and are judicious about who they perform it on.

Sep 06, 2011 7:43pm EDT  --  Report as abuse
KathyF wrote:
As a patient who had the duodenal switch operation 10 years ago, I am a little disturbed by conclusions of this study. To date, I have not had any problems with abdominal pain, vomiting, diarrhea or intestinal obstruction. Can these things happen? Sure. They also can happen with any other weight loss surgery. I often read on weight loss surgery boards of the difficulties those who have RNY or Lapband have had with vomiting, pain and strictures. Lapband, which is often touted as safer because it is “less invasive” often has problems with erosion and damage to the esophagus. And intestinal obstruction is common with any abdominal surgery… not just the duodenal switch. Nutritional difficulties are very manageable if one properly manages their supplementation and protein intake. I believe there would be much less problems with malnutrition if the patients get the proper aftercare. I have seen many who are given wrong nutritional advice from their surgeon and/or the surgeon’s nutritionist. Oftentimes they are given advice that is actually geared to a different surgery like the RNY. This is a big mistake as the nutritional requirements for the RNY and the Duodenal Switch is very different. Personally, I am very happy with my surgery as I feel it has given me the quality of life that I wouldn’t have otherwise with either never having surgery or having a different surgery.

Sep 06, 2011 8:18pm EDT  --  Report as abuse
Kllineaweaver wrote:
I have had the DS and am 10 years post op this April. I had my surgery done by one of the top 3 surgeons performing the DS, Dr. Robert Rabkin. He is/was (since retired)a Bariatric Surgeon. When I decided that this was an option for me I went to his office where I had to attend two pre op support groups, I had to be evaluated for my emotional state. I went to his informative meeting that talked about all weight loss procedures and not just the one he preferred, the DS. I was educated on the RNY, gastric bypass and the DS. I was also educated on how important my follow up labs are and what potential complications could happen long term. There are support groups all over. I’m 10 years out and am still in contact with my surgeons office. I have had 3 successful pregnancies, and healthy babies. I was not considered high risk. In fact what I have found is the lack of educated MD’s on the DS or any Weight Loss Surgery (WLS). They are quick to blame the DS in return the problem is not WLS related by any means. I have met many RNY pts. and the majority of them went to just a surgeon with no follow up care and have no idea how to deal with what is happening to them. I have also met DS pts. who have struggled but would do it over again and again if needed. I still highly recommend the DS! I don’t buy this article at all. RNY pts. can suffer from the dumping effect, their staples can pop, are prone to stomach ulcers. It’s all about doing your research. Check out Obesityhelp.com a great resource. Also there is a duodenal switch group on Facebook. I encourage you to look at all of the surgeries offered and see what is best for you. Just know that the lap band is backed by a Pharmaceutical company and has the money to put it out there. I have no stats to give you but I hear over and over that there are a lot of complications with this procedure.

Sep 07, 2011 1:50pm EDT  --  Report as abuse
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