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New studies examine adverse outcomes associated with obesity and more applicable measures of obesity

May 3, 2010
Digestive Disease Week
Pay-for-performance reimbursement models may create unintended financial incentives for doctors to discriminate against obese patients, measuring a patient's waist circumference may be more effective in predicting surgical outcomes than the more traditional body mass index measure, and childhood obesity doubles the risk of developing colon cancer, according to data being presented at Digestive Disease Week 2010.

Pay-for-performance reimbursement models may create unintended financial incentives for doctors to discriminate against obese patients, measuring a patient's waist circumference may be more effective in predicting surgical outcomes than the more traditional body mass index measure, and childhood obesity doubles the risk of developing colon cancer, according to data being presented at Digestive Disease Week® (DDW®) 2010. DDW is the largest international gathering of physicians and researchers in the field of gastroenterology, hepatology, endoscopy and gastrointestinal surgery.

"Doctors have long been aware of the toll that obesity takes on the body," said Christopher C. Thompson, MD, MSc, FASGE, Brigham & Women's Hospital. "These studies help us understand the specific ramifications of childhood and adult obesity and the increased risk that obesity poses when considering surgical outcomes."

Pay-for-Obesity? Performance Metrics Ignore Differences in Complication Rates and Cost for Obese Patients Undergoing Two Common General Surgical Procedures (Abstract #290)

New Medicare and Medicaid payment policies are intended to reward physicians for positive patient outcomes while cutting costs, but according to new research from the Johns Hopkins University School of Medicine, Baltimore, MD, such policies may actually provide financial incentives for doctors to discriminate against patients.

Pay-for-performance policies have grown in popularity over the last few years and are increasingly used to measure the quality of medical care. The premise behind the mechanism is to financially reward hospitals and doctors for good outcomes and punish for poor patient outcomes by adjusting reimbursement by one percent to two percent if an infection occurs within 30 days of surgery. According

to Martin Makary, MD, MPH, surgeon and associate professor of public health at the Johns Hopkins School of Medicine, such payment structures fail to account for patient factors that are out of the control of doctors yet influence outcomes, the most common being obesity, which can double a patient's chance of infection.

Studying national insurance claims of 36,483 patients who had undergone one of two common general surgical procedures, Dr. Makary, senior author of the study, found that obese patients undergoing appendectomy were 25 percent more likely to experience complications, and patients undergoing cholecystetomy were 7 percent more likely to have complications. In addition, Makary found that the cost of providing such care was higher for obese patients: the median total inpatient costs for obese patients after a basic gallbladder removal were $2,978 higher and $1,600 higher for appendectomy.

Because obesity rates are higher in minority populations -- black women have a 50 percent incidence of being overweight compared to 18 percent for white men -- Dr. Makary expressed concern for the discrimination implications under such payment structures. "What sounds good in theory turns out in reality to punish doctors who take care of more high-risk patients, and actually financially incentivizes discrimination," said Dr. Makary.

Dr. Makary points out that standardized outcomes accounting for patient factors would eliminate the unintended incentives to discriminate. The National Surgical Quality Improvement Program (NSQIP) is a doctor-initiated program that has developed such outcome measures.

Dr. Makary and Dr. Hirose will present these data on Monday, May 3 at 9 a.m. CT in 244-245, Ernest N. Morial Convention Center.

Waist Circumference Predicts Complications in Rectal Cancer Surgery (Abstract # 431)

A patient's waist circumference can serve as a predictor as to whether the patient will experience complications in recovering from rectal cancer surgery, according to researchers at the Michael E. DeBakey VA Medical Center (MEDVAMC) and Baylor College of Medicine (BCM).

"Being overweight or obese is known to impact a patient's ability to recover from surgery," said David H. Berger, MD, MHCM, co-author of the paper, MEDVAMC operative care line executive, and professor of surgery at BCM. "However, our study indicates abdominal fat is particularly relevant to abdominal surgical outcomes."

Dr. Berger and Courtney Balentine, MD, co-author of the paper and a fellow in surgical research at BCM, sought to find out if a patient's waist circumference could serve as a better indicator than body mass index (BMI) in determining whether a patient would have difficulty recovering from surgery. BMI is a common measurement that uses a person's height and weight to formulate a measure of overweight or obesity.

"It is our contention that BMI misses the nuances of obesity because it is unable to demonstrate where the fat is distributed on the patient," said Dr. Balentine.

The study of 150 patients who underwent rectal cancer surgery found heavier patients were twice as likely to experience complications than patients with a smaller waist circumference. Patients with a waist of 45 inches or more were three times more likely to experience surgical site infections and twice as likely to require reoperation after their initial surgery.

"This study provides important insight for surgeons planning to operate on a patient with heavy midline fat distribution," said Dr. Berger. "Necessary surgical procedures cannot be avoided, but surgeons may want to consider altering antibiotic dosages in order to better fight infection."

Past studies of BMI and surgical infections have had inconsistent findings. This study is the first using waist circumference as a predictor of short-term surgical complications.

Dr. Balentine will present these data on Monday, May 3 at 4:15 p.m. CT in 243, Ernest N. Morial Convention Center.

The Effect of Early-Onset Obesity on Adult-Onset Colon Neoplasia (Abstract #314g)

Obese adults who were overweight or obese in childhood and early adulthood are at twice the risk for developing colon cancer compared to adults with consistently normal weight, according to investigators from New York University (NYU). Findings could lead to more targeted colon cancer screening recommendations and preventative interventions.

Fritz Francois, MD, MS, assistant dean for academic affairs and diversity and assistant professor of medicine at NYU's Langone Medical Center, and colleagues studied the current and past body mass index (BMI) and waist circumference of 1,865 patients referred for a screening colonoscopy. Past BMIs were estimated from patient recall of body type and clothing size at ages 10 and 20. Each patient's level of obesity at specific age points were compared with the information from the screening colonoscopy, including the number, size and location of each polyp found.

From their analysis, investigators found a significant prevalence of polyps in patients who had been consistently overweight or obese (27 percent), especially compared to patients with consistently normal BMI (13 percent) and overweight BMIs at present (19 percent). This study also observed that specific racial and ethnic group participants were more likely to be obese at present and throughout their life, increasing their risk of polyps.

"Our findings suggest that the chronicity of obesity is a significant risk factor for developing colon cancer," said Dr. Francois. "Given the continued rise in early-onset obesity, especially in minority populations, there is a need for interventions and lifestyle modifications earlier in life to help lessen this serious health risk later in life."

Dr. Francois also noted that these findings might help clinicians better target individuals for screening colonoscopies.

While this study shows that obesity is an additional factor that predisposes individuals to colon cancer, individuals with normal weight are also at risk of developing colon cancer and should be screened.

Dr. Ian Fagan will present this data on Monday, May 3, at 8:30 a.m. CT in 280-282, Ernest N. Morial Convention Center.

Efficacy and Safety of Intragastric Balloon for Obesity and Pre-Obese Patients: A Brazilian Experience (Abstract #M1515)

New research from Gastroendo Medical Group in Brazil has found intragastric saline-filled balloons to be a safe, effective and minimally invasive weight-loss treatment for pre-obese and obese patients, and may offer an alternative weight-loss treatment option for patients who may not be eligible for gastric bypass to reduce the morbidity and mortality associated with obesity.

Since the initial designs in the 1980s, the intragastric balloon procedure designs have progressed to eliminate many of the complications initially associated with the procedure, namely a smooth, seamless balloon constructed from a long-lasting material with a low ulcerogenic (tending to develop into ulcers) and obstruction potential, as well as the ability to adjust the balloon size and to fill the balloon with fluid instead of air. While this procedure has been employed internationally and in the U.S. for some time, this study may help establish expanded indications for intragastric balloon procedures including pre-obese patients.

Over a 15 month period, 81 patients completed the study using the intragastric balloon. Patients were divided along BMIs in four grades: pre-obese (BMI < 30), obesity grade 1 (BMI 30-34.9), obesity grade 2 (BMI 35-39.9) and obesity grade 3 (BMI ≥ 40). Prior to the procedure, each patient had failed to respond to previous clinical treatment for weight loss including, a calorie-restricted diet, physical activity, behavior modification and pharmacotherapy.

Researchers, led by Paula Elia, MD, at Gastroendo, performed the placement and subsequent removal of the balloon under propofol sedation. Balloons were smoothly inserted into the stomach by traction under direct endoscopy vision and were positioned in the upper stomach position. The balloon was filled with a saline solution and methylene blue, to help in locating and removal of the balloon. Patients were followed for five to seven months in a multidisciplinary clinical setting, including a gastroenterologist, endocrinologist, nutritionist, psychologist and psychiatrist. The balloon was removed after the five to seven month observation.

Participants across all obesity grades experienced significant weight loss, losing an average of 9.18 percent of initial weight. Patients with an obesity grade 3 experienced a more significant average weight loss of 12.2 percent of initial weight.

"This study reinforces the concept, efficacy and safety of intragastric balloon procedures for treatment of overweight and obesity," said Dr. Elia. "This is a reversible procedure that can be considered as an alternative weight-loss treatment option, particularly in pre-obese patients with a history of failure in other clinical treatments."

Dr. Elia cautioned that the intragastric balloon and intragastric balloon procedures are not a miracle weight loss method; after the balloon is extracted, weight loss maintenance depends exclusively on a combination of a calorie-restricted diet, physical activity and behavior modification.

Dr. Elia will present these data on Monday, May 3 at 8 a.m. CT in Hall F, Ernest N. Morial Convention Center.

Intragastric Air-Filled Balloon with New Features for Obesity (Bioflex): Preliminary Results (Abstract #W1582) A new study from the Hospital Sírio Libanês in Sao Paolo, Brazil, suggests that a new endoscopic method using an air-filled balloon could help obese patients maintain weight loss.

Researchers led by Kiyoshi Hashiba, MD, associate professor of the surgical department at Sao Paolo University, sought to develop a balloon treatment to capture images in the stomach and small intestine using newer features to improve the safety of placement and removal of the balloon. Theirs contained a device wall with two covering sheets, one made of silicon and the other with polyurethane. It also has a valve connected to a plastic tube for inflation, along with another tube containing a needle, which is used for reinflation, deflation and retrieval.

Investigators used a Bioflex balloon (BioB), an air balloon, and inserted it with 600 ml of air over a guide wire on six patients with an average BMI of 35.8 (obese). The guide wire is necessary because unlike other balloons, it does not require manual maneuvers inside the mouth during insertion. Balloon placement and removal were conducted under general anesthesia and endotracheall intubation and removal was planned for six months, or earlier in the event of intolerance, complications or desinsuflation of the balloon.

The balloon was completely deflated at the second month in two patients for whom it had to be replaced. Investigators did not find complications in any patients such as gastric perforation, ulceration, bleeding or acid reflux. The average weight loss was a loss of BMI of minus four.

Another important feature is the connection to a tube with a needle that allows deflation easy retrieval, which permits reinflation, allowing a longer and therefore more productive scan. Since the BioB is an air balloon and the patient does not need to be an inpatient, the costs will decrease. It also allows the use of BioB for long enough to change the habits of the patient.

The study showed that BioB presents an interesting, non-invasive option for obese patients. The balloon is an aid to the obese patient to help them change their behavior, since BioB causes the initial satiety, but that eventually decreases. Satiety can be reestablished with reinflation or overinflation.

Although the treatment is not recommended for morbidly obese patients because of complications with imagery, the fact that 45 percent of obese patients are not morbidly obese means there are still many patients who could benefit from this treatment.

Dr. Hashiba will present these data on Wednesday, May 5 at 8 a.m. CT in Hall F, Ernest N. Morial Convention Center.

Digestive Disease Week® 2010 (DDW®) is the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery. Jointly sponsored by the American Association for the Study of Liver Diseases, the AGA Institute, the American Society for Gastrointestinal Endoscopy and the Society for Surgery of the Alimentary Tract, DDW takes place May 1 -- May 5, 2010 in New Orleans, LA. The meeting showcases more than 5,000 abstracts and hundreds of lectures on the latest advances in GI research, medicine and technology.

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Digestive Disease Week. "New studies examine adverse outcomes associated with obesity and more applicable measures of obesity." ScienceDaily. ScienceDaily, 3 May 2010. <>.
Digestive Disease Week. (2010, May 3). New studies examine adverse outcomes associated with obesity and more applicable measures of obesity. ScienceDaily. Retrieved July 19, 2024 from
Digestive Disease Week. "New studies examine adverse outcomes associated with obesity and more applicable measures of obesity." ScienceDaily. (accessed July 19, 2024).

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