Measuring the percentage of weight regained following the maximum amount of weight loss after bariatric surgery can help predict a patient's risk of several serious health problems, according to a long-term, multicenter study led by University of Pittsburgh Graduate School of Public Health researchers.

The results, published today in JAMA, also found that, while on average study participants achieved maximum weight loss at two years post-surgery, when they reached that milestone varied substantially, with approximately 20% continuing to lose weight more than four years post-surgery.

No matter when maximum weight loss occurred, the rate of weight regained was highest in the first year following maximum weight loss. This indicates early detection and treatment of weight regain may be important.

Weight Regain

"Clinicians and patients want to know the extent of weight regain following bariatric surgery and how it may affect their health. However, the lack of a standard measure of weight gain and variable follow-up has led to inconsistent results across studies," said lead author Wendy C. King, Ph.D., associate professor in Pitt Public Health's Department of Epidemiology.

"Our study will help clinicians and patients understand the timeline, magnitude and impact of weight regain, as well as lead to further studies on how to best avoid and manage weight regain for better health outcomes," said King.

King and her colleagues followed 1,406 adults who had undergone Roux-en-Y gastric bypass surgery, measuring their weight an average of 8.3 times over a period that averaged 6.6 years.

The participants were enrolled in the National Institutes of Health-funded Longitudinal Assessment of Bariatric Surgery-2 (LABS-2), a prospective observational study of patients undergoing weight-loss surgery at one of 10 hospitals across the United States.

In addition to the percentage of weight loss that was regained, the team considered several other ways to characterize weight regain following maximum weight loss, including as a measure of body mass index, as a percentage of pre-surgery weight, as a percentage of lowest weight and number of kilograms regained.

To assess health outcomes, they looked at the progression of diabetes, high cholesterol and high blood pressure; and declines in physical and mental health-related quality of life and satisfaction with surgery.

To understand how to calculate weight regain this way, take someone who lost 150 pounds after bariatric surgery, then regained 28 pounds. That person regained 19% of their maximum weight loss.

This level of weight regain was associated with a 51% higher risk of diabetes progression and a 28% higher risk of decline in physical health-related quality of life, indicating to a clinician this level of weight regain may lead to the progression or development of various health problems.