As the rate of national obesity has steadily increased across all age groups, so has Americans’ willingness to turn to an effective surgical intervention to address severe obesity: bariatric surgery.

From 1996 to 2002 the use of bariatric surgery has increased seven-fold nationally, and its use has more than tripled among youth. More than 80 percent of individuals in all age groups who underwent the procedure were female.

These findings, from researchers at the University of Michigan Health System, also reveal that in 2002 alone, hospitals charged more than $2 billion for bariatric surgery, with private insurers picking up more than 80 percent of the charges.

Results from this study, which also examine the most common medical conditions among youth who undergo bariatric surgery, are reported in the January issue of Archives of Surgery.

Bariatric surgery, which includes procedures such as gastric bypass, gastric banding and biliopancreatic diversion, aims to change the gastrointestinal tract so it restricts the amount of food a person is able to consume.

As the nation’s waistline has continued to grow, so has the popularity of this weight loss procedure as more Americans work to combat their obesity after failed attempts at diet and exercise. The procedure is recommended only for individuals with severe obesity, or for those who are obese and suffering from other medical complications of obesity such as diabetes.

“The greatest increase in bariatric surgery rates has occurred among non-elderly adults, and, for the first time, we’‘ve seen that bariatric surgery rates have increased among the nation’s youth, more than three-fold from 1996 to 2002,” notes study lead author Matthew M. Davis, M.D., M.A.P.P., an assistant professor of pediatrics, internal medicine and public policy in the Child Health Evaluation and Research (CHEAR) Unit in U-M C.S. Mott Children’s Hospital’s Division of General Pediatrics.

However, Davis says key aspects of this national trend – the female to male ratio among patients undergoing the procedure in various age groups, additional medical conditions patients may have beyond obesity, and the economic implications of the procedure – remained unclear and required closer examination.

Using data from Nationwide Inpatient Sample (NIS), a database of discharge information developed by federal and state governments and health care institutions, Davis and his colleagues analyzed the most recent data available,1996 through 2002, to examine trends in the use of bariatric surgery.

For the study, individuals who had undergone bariatric surgery were characterized according to gender, age, and other medical conditions, or comorbidities, they may have in addition to obesity. Their hospitalization was examined based on length of stay, average hospital charges, expected primary payer, and in-hospital mortality.

Nationally, the study revealed that rates of bariatric surgery climbed seven-fold from1996 through 2002, with increases in all age groups studied: youth (younger than 20 years of age), non-elderly (20 to 65 years of age) and elderly (older than age 65).

And this increase is having a noticeable impact on health insurance: in 2002, hospitals charged more than $2 billion for these procedures, with more than 80 percent billed to private insurers. On average, each hospital stay in 2002 for bariatric surgery led to about $29,000 in charges.

“Private payers are shouldering an increased share of the costs for bariatric surgery, and this trend is most likely a result of increased coverage among private payers for this procedure, which has a track record of success compared to other therapies for obesity,” says Davis. “Bariatric surgery appears to be an increasingly attractive option for private insurance plans and employers that face rapidly growing health care costs associated with obesity and related comorbidities.”

While the greatest increase in bariatric surgery rates occurred among non-elderly adults, Davis says this is the first study of its kind to report that bariatric surgery rates also have grown among America’s youth, with bariatric procedures in this age group more than tripling during the time period studied.

Unlike previous national studies on bariatric surgery, Davis’ research further identified the most common comorbidities among youths undergoing bariatric surgery. In 2002, comorbidities of obese youth were: depression (17 percent), high blood pressure (14 percent), esophageal reflux (14 percent), sleep apnea (11 percent), chronic gallstones (11 percent), and asthma (8 percent).

Gender-related findings among the youth population also mirrored those of the non-elderly group in the study. In both age groups, women were four times more likely to undergo bariatric surgery than men.

“This finding suggests that, in addition to medical factors, there are likely some social factors playing into the decision to undergo bariatric surgery that leads to young women being more likely, and young men less likely, to have the procedure,” says Davis, noting that other national data indicate a more balanced gender ratio among youth in relation to severe obesity.

Along with Davis, the study was co-authored by Kathryn Slish, MA, Department of Pediatrics at the U-M Health System; Celia Chao, M.D., Department of Surgery at the University of Texas Medical Branch; and Michael D. Cabana, M.D., MPH, Department of Pediatrics at the University of California at San Francisco.