There will be nearly ten times as many operations performed for weight loss in 2005 as there were in 1998

There will be nearly ten times as many operations performed for weight loss in 2005 as there were in 1998, report researchers from the University of Chicago and the University of California at Irvine in the 19 October 2005 issue of JAMA: The Journal of the American Medical Association, but the groups that need surgery the most are not the ones driving the increase.

Surgeons performed an estimated 13,365 bariatric procedures, primarily gastric bypass operations, in 1998. In four years that had doubled and doubled again, to 72,177 in 2002. The authors project 102,794 such operations in 2003; 130,000 in 2005 and as many as 218,000 by 2010.

Recent growth, they note, was "substantially higher than that previously reported."

Along with the rapid increase in number of cases there was a slower but substantial shift toward patients who were from wealthier households and with private insurance.

"As surgical treatment for obesity increased, disparities in receipt of bariatric surgery increased with men, those with public insurance, and those residing in lower income areas less likely to undergo surgery over time," said the study's lead author, Heena Santry, M.D., surgical resident at the University of Chicago Hospitals.

"As long as bariatric surgery remains the only durable option for weight loss in the morbidly obese," she said, "we need to make an effort to ensure that all populations who suffer from morbid obesity have the option of surgical weight-loss irrespective of insurance provider or income level."

Morbid obesity, defined as a body mass index of 40 or greater (or 35 with additional medical problems), has become disturbingly common. In 1986, one out of 200 U.S. adults had a BMI of 40 or above. By 2002 that had risen to one out of 20, with even higher rates among those with lower incomes and less education.

The researchers, Santry and colleagues Diane Lauderdale, Ph.D., of the University of Chicago and Daniel Gillen, Ph.D., of UC Irvine, worked with data from the Nationwide Inpatient Sample, which represents 20 percent of admissions to all U.S. acute-care hospitals.

They found that as bariatric surgery gained popularity and surgical techniques improved, it became more and more an option for those with private insurance and those residing in higher income areas, a trend they call "worrisome."

In 1998, for example, about one out of four patients (24.7%) lacked private insurance. By 2002 that had fallen to one out of six (17.1%)

In 1998, 32 percent of patients came from households located in zip codes with an average income greater than $45,000 a year (from 1990 census data, the highest available category). By 2002, that had nearly doubled to 60 percent.

"This income bracket has driven the increase," said Santry. In 1998, there were 4,269 patients from this group. By 2002, that had increased ten fold, to 43,055.

"The data don't allow us to determine whether the increased popularity of bariatric surgery among wealthier persons is a result of differences in access to care or patient choice," said co-author Lauderdale.

Surgical treatment for those from less wealthy neighborhoods also increased but at a much slower pace.

The authors found that despite a shift toward higher-risk patients, in-hospital complications remained stable and length of hospital stay decreased from 4.5 days in 1998 to 3.3 days in 2002.

As obesity spreads, surgical treatment increases and procedures improve, "policymakers should examine the factors associated with the uneven use of bariatric surgery," the authors suggest.

They also note that although 36 percent of obese adults are male, only 20 percent of obesity surgical patients are men.

Public health campaigns, they suggest, may "help shift thinking about obesity from a cosmetic concern of women to a health concern for both sexes."