CHICAGO — Obesity surgery helps patients do more than shed weight — it often cures their diabetes, high blood pressure and high cholesterol, researchers say.
The research — an analysis of 136 studies — found that such operations are more than cosmetic. They appear to alter the patient's body chemistry itself and eliminate or relieve conditions that can lead to heart attacks, strokes and kidney failure.
The analysis was funded by a Johnson & Johnson Co. subsidiary that develops and markets surgical instruments, including staplers for obesity surgery. But the results echo what many doctors have reported seeing.
Diabetes was eliminated in nearly 77 percent of the affected patients; high blood pressure was eliminated in nearly 62 percent; cholesterol improved in at least 70 percent; and obstructive sleep apnea — episodes when breathing stops during sleep — disappeared in almost 86 percent. All four conditions are strongly linked to obesity and can have lethal consequences.
The study appears in Wednesday's Journal of the American Medical Association.
University of Minnesota surgeon Dr. Henry Buchwald, the study's lead author and a consultant to the Johnson & Johnson subsidiary, said there is evidence that when the intestinal tract is rearranged in obesity surgery, patients who were diabetic are "cured" even before they start shedding significant amounts of weight.
That may be because such operations alter the intestinal hormones, he said.
Also, doctors have long known that losing weight helps improve blood pressure and cholesterol levels by reducing stress on the cardiovascular system.
About two-thirds of U.S. adults are overweight, and of those, almost half are grossly overweight, or obese. Surgery in which the stomach is reduced or restricted is typically reserved for extremely obese people who are at least 100 pounds heavier than their recommended weight and for whom other weight-loss methods have failed.
Buchwald and colleagues reviewed studies on obesity surgery published in English between 1990 and 2003. The studies involved 22,094 patients ages 16 to 64, at least two-thirds of them women.
The researchers found patients lost an average of 61 percent of their excess weight.
The greatest weight loss occurred with the most complicated surgery, an operation called a duodenal switch, which is more common in Europe. It involves removing three-fourths of the stomach and rearranging the intestine so digestion occurs in a shortened channel, resulting in less food being absorbed.
The most common U.S. obesity surgery, gastric bypass, involves creating an egg-sized pouch in the upper stomach and attaching it to a section of intestine. The procedure reduces the amount of food patients can eat and results in less food being absorbed. The researchers found it resulted in a 62 percent loss of excess weight.
Obesity surgery is a major operation, not cosmetic tinkering, Buchwald emphasized. The risks include malnutrition, stomach problems, infections and, in rare cases, death.
The average 30-day death rate following surgery was about 0.6 percent in the reviewed studies. Buchwald said nonfatal complications also occurred but no more than with other major surgery.
A report last week from the government's Agency for Healthcare Research and Quality said about 20 percent of obesity-surgery patients experience complications, most of them minor. The report also said surgery is more effective than other methods for weight loss and for controlling obesity-related ailments.