NEW YORK (Reuters Health) - Gastric bypass surgery is more likely to result in successful weight loss, both short and long term, than is gastric banding, according to one of the first head-to-head comparisons of the two most commonly used surgeries in obese patients.

Patients who underwent the bypass procedure also lost more weight and showed more consistent weight loss, Dr. Nancy Puzziferri of The University of Texas Southwestern Medical Center in Dallas and colleagues report.

Although evidence supports a faster weight loss with gastric bypass, 3 years after surgery the results of bypass and banding were the same, Puzziferri and her colleagues note.

However, the pros and cons of each procedure need to be weighed for each patient, they add. Bypass is a riskier and more complicated surgery, and banding requires more intensive follow-up.

"Risk-benefit ratios and the patient's ability to return to clinic are critical factors in choosing which procedure better suits a particular patient," they write in the Annals of Surgery.

To better understand how outcomes compare for the two procedures, Puzziferri's team evaluated 1,102 patients who had undergone gastric bypasses and 631 who had gastric banding at their center between 1997 and 2006. A total of 1,518 patients were available for evaluation.

Bypass patients lost more weight, lost it faster, and were less likely to have transient weight gain than patients who had the band procedure. The results of the bypass procedure were also more consistent from patient to patient.

While 18.1 percent of the band patients had lost less than 25 percent of their body weight 2 years later (the goal was 40 percent or more), just 2.6 percent of bypass patients did.

While 53.2 percent of the bypass patients lost at least 75 percent of their excess body weight by the study's end, 9.8 percent of the patients who underwent banding did.

The bypass patients were more than 18-times as likely as the banding patients to have achieved successful weight loss within 6 months of having the procedure, and 2 years out their odds of success were 9-times greater.

Weight loss with gastric banding is similar to the gradual loss seen with low-calorie diets, the researchers note. "Behavioral practices may be more critical to weight loss success in gastric band than in gastric bypass," they suggest.

"Despite its higher operative risk, gastric bypass may be a better choice for selected patients," the researchers add. They suggest that a larger study with at least 5 years of follow-up is needed to clarify how the risks, benefits and costs of the two procedures compare.

SOURCE: Annals of Surgery, August 2008.

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