Hospital label no guarantee of better weight surgery

* Bariatric surgery "centers for excellence" not better

* Complication rates comparable with other hospitals

* Separate study looks at benefits for super obese

CHICAGO, April 20 (Reuters) - Despite the fancy label, hospitals designated bariatric surgery "centers of excellence" have as many deaths and complications from the weight-loss procedure as others, U.S. researchers said on Monday.

The extra cost and effort required by hospitals to earn such a designation might not be worth it, they said.

"Designation as a bariatric surgery center of excellence does not ensure better outcomes," Dr. Edward Livingston of the University of Texas Southwestern School of Medicine, whose study appears in the Archives of Surgery, said in a statement.

Bariatric surgery is becoming an increasingly popular treatment for obesity. It works by altering the digestive tract to reduce the volume of food that can be eaten and digested.

A separate study in the same journal looked at the benefits of the surgery in severely obese patients.

Large insurance companies and Medicare, the federal health plan for 44 million elderly and disabled Americans, help pay for the surgery -- which costs from $15,000 to $35,000 -- in severely obese people. And many payers, including Medicare, require the procedures to be done at hospital designated as a bariatric center of excellence.

Livingston wanted to see if patients at these centers actually got better care. He analyzed 2005 data on 19,363 patients who had bariatric surgery, including 5,420 patients whose surgery was performed at a center of excellence.

He found that 1.7 percent of bariatric surgery patients treated at a center of excellence died and 6.3 percent developed complications. That compared with a death rate of .09 and a complication rate of 6.4 percent at hospitals without a center of excellence designation.

Because a "center of excellence" designation requires hospitals to hire extra staff, they are costlier to run, yet these "extra expenses associated with center of excellence designation may not be warranted," Livingston wrote.

A separate study in the same journal looked at the effects of gastric bypass surgery in two groups of severely obese patients: the morbidly obese -- those with a body mass index of 40 to 49 -- and the super obese -- those with a body mass index of 50 or higher.

Body mass index, or BMI, is a formula that takes into account a person's height and weight. A BMI of 30 is considered obese, while a BMI of 25 to 30 is considered overweight.

Dr. Michel Suter of Hopital du Chablais in Lausanne, Switzerland, and colleagues studied 492 morbidly obese patients and 133 super obese patients treated with gastric bypass between 1999 and 2006.

They found that while the super obese patients lost more weight (37.3 percent of their body weight) than the morbidly obese patients (34.7 percent of their body weight), fewer than half of the super obese got down to being merely overweight six years after the surgery, compared with more than 90 percent of the morbidly obese patients.

Despite these differences, they said improvements in quality of life and other health measures were similar in both groups. Previous studies have found obese people who have weight-loss surgery are less likely to die from heart disease, diabetes and cancer than obese people who do not.

Editing by Maggie Fox