Paper of the Month: The weight is over

About the School of Medicine Paper of the Month

The School of Medicine newsletter spotlights a recently published faculty research paper in each issue. The goals are to highlight the great research happening at OHSU and to share this information across departments, institutes and disciplines. The monthly paper summary is selected by Senior Associate Dean for Research Mary Stenzel-Poore, Ph.D., Associate Dean for Clinical Science Eric Orwoll, M.D., and Assistant Dean for Basic Research Mary Heinricher, Ph.D.


This month's School of Medicine featued paper is from Bruce Wolfe, M.D., and is titled, "Weight change and health outcomes at 3 years after bariatric surgery among individuals with severe obesity." It was published in the Journal of the American Medical Association.

January 31, 2014 

Dr. WolfeWeight change and health outcomes tracked 3 years after bariatric surgery among individuals with severe obesity

Some could argue that obesity is one of the 21st century's most pressing problems. A health risk worldwide, effecting young and old, the obesity epidemic is as enormous as it is complex. 

Obese patients often suffer from day-to-day health issues like fatigue and stress. For many, fighting obesity through diet and exercise is a way of life – often filled with ups and downs. But for severely obese patients, in particular people who have a body mass index of greater than 35, obesity can lead to serious risks, conditions that have an adverse effect on health. These diseases include type-2 diabetes, hypertension, dyslipidemia, degenerative arthritis, kidney disease or several other medical conditions. 

Diet, exercise and medications may accomplish temporary weight loss among the severely obese, but the weight is usually regained. In fact, patients suffering from severe obesity have often become candidates for bariatric surgery, which includes a variety of procedures performed to reduce the size of the stomach. For years, successful bariatric surgery has resulted in large, sustained weight loss for severely obese patients, thus improving the quality of life. However, since the surgeries first began in the 1950s, little has been done to systematically document outcomes among individuals with severe obesity, which includes long-term tracking patients for possible complications and the status of comorbid diseases.

"Despite the increasing use of bypass surgeries to treat obesity, there are remarkable and poorly understood effects on associated metabolic abnormalities," said Eric Orwoll, M.D., associate dean for clinical research. "January's School of Medicine's Paper of the Month presents the first large scale study to track weight and selected health parameters after either bariatric bypass or adjustable gastric banding surgeries."

The paper, "Weight change and health outcomes at 3 years after bariatric surgery among individuals with severe obesity," published in the Journal of the American Medical Association, presents data on 2,450 patients. "Although previous studies have tracked various types of bariatric procedures, few of them report findings beyond two years post-surgery or provide a broad population for statistical analysis," said Bruce Wolfe, M.D., professor of surgery and lead investigator of the study. "Additionally, comorbid conditions such as diabetes have not been consistently tracked."

Unique aspects of Dr. Wolfe and team's study include a rigorous data collection strategy that resulted in an impressive 92 percent follow-up rate. "Significantly, the study found that weight loss resulting from gastric bypass surgery was twice the amount that resulted from adjustable banding," said Dr. Wolfe.

Additionally, in both procedures, the investigators found that the majority of weight loss was evident one year after surgery. A variety of trajectories for weight loss were documented for each type of surgical intervention, information that Dr. Wolfe said would "help physicians better understand variability in weight loss outcomes and ultimately help identify patients who will benefit the most from targeted interventions." Additional findings showed that health improvements in diabetes, blood pressure and lipids were variable, but significantly partial remission of type-2 diabetes was reported in 67 percent of patients undergoing bariatric bypass surgery. 

The study was conducted by Dr. Wolfe and a team of scientists in the multicenter research consortium Longitudinal Assessment of Bariatric Surgery (LABS), an NIH-funded consortium of six clinical centers and a data coordinating center working in cooperation with NIH scientific staff to plan, develop and conduct coordinated clinical, epidemiological and behavioral research in bariatric surgery.  

Dr. Wolfe, chair of LABS, said he and the LABS consortium will continue to follow the cohort of patients for many years, and will be able to provide exceptional data necessary to understand the complexities of obesity, comorbid conditions and the long term impact of bariatric interventions. 

"Long-term goals include utilization of this unique patient population to identify the incidence and severity of long-term complications and details of the relationship of obesity and the response to surgery among 15 separate domains, including diabetes, hypertension, sleep apnea and psychosocial manifestations of obesity," said Dr. Wolfe.

In underscoring the importance of the LABS consortium work, Dr. Orwoll said, "This study teaches us again about the advantages of a well-coordinated team approach to science. It provides data that are absolutely necessary to understand the impact of the procedure and to unravel its biological mechanisms."