Department of Research & Evaluation News

PASADENA, Calif. –  Non-Hispanic white patients who underwent a gastric bypass procedure lost slightly more weight over a three-year period than Hispanic or black patients, according to a Kaiser Permanente study published in the journal Surgery for Obesity and Related Diseases. The study also examined two types of bariatric surgery and found that patients who underwent the now common gastric bypass procedure lost more weight over the same period than patients who underwent the more recently developed vertical sleeve gastrectomy procedure. 

Researchers examined the Kaiser Permanente electronic health records of more than 20,000 racially and ethnically diverse patients in Southern California who underwent bariatric surgery from 2004 through May 2013. They found that, on average, at three years following gastric bypass surgery, non-Hispanic white patients lost 63 percent of their excess weight; Hispanic patients lost 59 percent; and black patients lost 56 percent. With vertical sleeve gastrectomy patients, the researchers found no significant differences between racial or ethnic groups in the percentage of excess weight lost. 

The study also found that overall, gastric bypass patients lost an average of 59 percent of excess weight (an average 81.5 pounds) and vertical sleeve gastrectomy patients lost an average of 46 percent (57.6 pounds) after three years of follow-up. 

Studies have shown that bariatric surgery is associated with sustainable weight loss for patients with extreme obesity, but there is very little research to show how these procedures affect persons of different races and ethnicities, especially in the long term, said study lead author Karen J. Coleman, PhD, of the Kaiser Permanente Southern California Department of Research & Evaluation. To address the current gaps in the knowledge about bariatric surgery, we created a registry of patients who underwent surgery to monitor quality and safety outcomes and assist clinicians who are caring for these patients after their surgery.

Bariatric surgery is an option for people who cannot lose weight by other means or who suffer from serious health problems related to extreme obesity. Gastric bypass is the most commonly performed bariatric surgical procedure and involves the creation of a small pouch at the top of the stomach for food intake, limiting the amount of food that can be consumed, in addition to a bypass of the upper small intestine to limit food absorption. Vertical sleeve gastrectomy is a procedure involving the removal of part of the stomach with the remaining portion formed into a tube, limiting food intake. This surgery has most often been conducted on patients who are too heavy to safely have other types of weight-loss surgery because the procedure can be completed more quickly and has less risk of long-term complications. 

According to the Centers for Disease Control and Prevention, nearly 34 percent of U.S. adults are considered to be obese, with a body mass index of 30 or greater, and nearly 6 percent of Americans are considered to have extreme obesity, with a BMI of 40 or greater. Obesity has been found to be more common among black and Hispanic populations, with nearly 50 percent of blacks, 39 percent of Hispanics and 34 percent of non-Hispanic whites considered to be obese, according to the National Institutes of Health. Obese individuals are often at a greater risk of health problems, including coronary heart disease, high blood pressure, stroke and type 2 diabetes. The NIH considers extreme obesity a chronic condition that is hard to treat with diet and exercise alone. 

Even though some patients may not lose as much weight as others, the weight regain rate at three years is still very low for all patients, regardless of their racial or ethnic background. This supports the success of bariatric surgery for weight control in persons who have extreme obesity, said Coleman. We believe our study provides an opportunity for health care providers to potentially develop more culturally sensitive post-surgical programs to improve success rates for populations struggling with weight loss. 

This study is part of Kaiser Permanente’s broader efforts to deliver transformational health research focusing on bariatric surgery and its impact on patients with extreme obesity. Last October, a Kaiser Permanente study found that the impact of bariatric surgery on risk factors for cardiovascular disease depends upon a variety of factors, including the type of surgery, sex of the patient, race and ethnic background and pre-surgery body mass index. A separate Kaiser Permanente study also found that the chronic use of prescription painkillers, also known as opioids, among obese patients prior to bariatric surgery continues after surgery.

Other study authors include Yii-Chieh Huang, MS, of the Kaiser Permanente Southern California Department of Research & Evaluation; Fadi Hendee, MD, of the Department of Endocrinology, Kaiser Permanente South Bay Medical Center ; Heather Watson, MA, Population Care Management, Southern California Permanente Medical Group; Robert A. Casillas, MD, of the Department of Surgery, Kaiser Permanente West Los Angeles Medical Center; and John Brookey, MD, Quality Improvement, Patient Safety, Southern California Permanente Medical Group.

About the Department of Research & Evaluation

The Department of Research & Evaluation conducts high-quality, innovative research into disease etiology, prevention, treatment and care delivery. Investigators conduct epidemiology, health sciences and behavioral research as well as clinical trials. Areas of interest include diabetes and obesity, cancer, HIV/AIDS, cardiovascular disease, aging and cognition, pregnancy outcomes, women’s and children’s health, quality and safety, and pharmacoepidemiology. Located in Pasadena, Calif., the department focuses on translating research to practice quickly to benefit the health and lives of Kaiser Permanente Southern California members and the general population. Visit kp.org/research.

About Kaiser Permanente
Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America’s leading health care providers and not-for-profit health plans. Founded in 1945, our mission is to provide high-quality, affordable health care services and to improve the health of our members and the communities we serve. We currently serve approximately 9.1 million members in eight states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the-art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health. For more information, go to kp.org/share.