Duodenal Switch = better weight loss + more adverse events?

SOURCE: bit.ly/mQAUrf 

Annals of Internal Medicine, online September 6, 2011.

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.

Study - 

Background: Gastric bypass and duodenal switch are currently performed bariatric surgical procedures. Uncontrolled studies suggest that duodenal switch induces greater weight loss than gastric bypass.

Objective: To determine whether duodenal switch leads to greater weight loss and more favorable improvements in cardiovascular risk factors and quality of life than gastric bypass.

Design: Randomized, parallel-group trial. (ClinicalTrials.gov registration number:NCT00327912)

Setting: 2 academic medical centers (1 in Norway and 1 in Sweden).

Patients: 60 participants with a body mass index (BMI) between 50 and 60 kg/m².

Intervention: Gastric bypass (n = 31) or duodenal switch (n = 29).

Measurements: The primary outcome was the change in BMI after 2 years. Secondary outcomes included anthropometric measures; concentrations of blood lipids, glucose, insulin, C-reactive protein, and vitamins; and health-related quality of life and adverse events.

Results: Fifty-eight of 60 participants (97%) completed the study. The mean reductions in BMI were 17.3 kg/m² (95% CI, 15.7 to 19.0 kg/m²) after gastric bypass and 24.8 kg/m² (CI, 23.0 to 26.5 kg/m²) after duodenal switch (mean between-group difference, 7.44 kg/m² [CI, 5.24 to 9.64 kg/m²]; P < 0.001). Total cholesterol concentration decreased by 0.24 mmol/L (CI, −0.03 to 0.50 mmol/L) (9.27 mg/dL [CI, −1.16 to 19.3 mg/dL]) after gastric bypass and 1.07 mmol/L (CI, 0.79 to 1.35 mmol/L) (41.3 mg/dL [CI, 30.5 to 52.1 mg/dL]) after duodenal switch (mean between-group difference, 0.83 mmol/L [CI, 0.48 to 1.18 mmol/L]; 32.0 mg/dL [CI, 18.5 to 45.6 mg/dL]; P ≤ 0.001). Reductions in low-density lipoprotein cholesterol concentration, anthropometric measures, fat mass, and fat-free mass were also greater after duodenal switch (P ≤ 0.010 for each between-group comparison). Both groups had reductions in blood pressure and mean concentrations of glucose, insulin, and C-reactive protein, with no between-group differences. The duodenal switch group, but not the gastric bypass group, had reductions in concentrations of vitamin A and 25-hydroxyvitamin D. Most Short Form-36 Health Survey dimensional scores improved in both groups, with greater improvement in 1 of 8 domains (bodily pain) after gastric bypass. From surgery until 2 years, 10 participants (32%) had adverse events after gastric bypass and 18 (62%) after duodenal switch (P = 0.021). Adverse events related to malnutrition occurred only after duodenal switch.

Limitation: Clinical experience was greater with gastric bypass than with duodenal switch at the study centers.

Conclusion: Duodenal switch surgery was associated with greater weight loss, greater reductions of total and low-density lipoprotein cholesterol concentrations, and more adverse events. Improvements in other cardiovascular risk factors and quality of life were similar after both procedures.

 

This Livingstone sounds like a quack. Especially this:

There was no evidence that surgery improved longevity over the next seven years.

Seven years isn't very long to be looking at increased longevity. There are other studies that show WLS does increase longevity. 

Plus many of the deficiencies he attributed to the DS group are pretty common in RnYers especially iron, Vitamin D and calcium deficiencies. But he made it seem like only DSers experience those deficiencies.

To get published a study has to contain new and exciting information. Truth is optional.

*Like!*

hahah, this says it all, this article is flawed in so many ways....ahhh ignorance is blisssssss

Well Said!!

I think that the number of participants in the study was too small to reach such conclusions. And yes, there are more risks of nutritional deficiencies... but they are, in most cases, very manageable if the patient is given proper aftercare advice.

And don't get me started about the "survival benefits" and whether it actually lengthens people's lives or not. How about quality of life? I think that counts for a lot too.

Interesting that they point out problems like "abdominal pain, vomiting, diarrhea and intestinal obstruction" and only attribute them with the duodenal switch... yet we all know that these very same issues can occur with the RNY also. Heck, they don't even point out that intestinal obstruction can, and does, occur with any abdominal surgery. Has nothing to do with the type of surgery you have. I seriously sense a skewed agenda in these conclusions.

[edited to remove personal information]

 As someone living with constant intestinal pain -- I also questioned that.

"And don't get me started about the "survival benefits" and whether it actually lengthens people's lives or not. How about quality of life? I think that counts for a lot too."

YES YES YES...thank you! Totally agree!