Results from a Geisinger Obesity Institute study suggest Roux-en-Y gastric bypass (RYGB) surgery has durable protective effects with regard to congestive heart failure. This is the first time a study has shown such long-term benefits, according to researchers.
“Many studies have demonstrated that the Framingham Risk Score is favorably affected by weight-loss surgery,” says Peter Benotti, MD, Senior Clinical Investigator at the Pennsylvania-based Geisinger Obesity Institute. The Framingham Risk Score predicts a person’s risk of developing cardiovascular disease within the next 10 years based on a summary of factors. “The importance of our study is that it translated these risk factors into hard cardiovascular outcomes.”
An Expanded View
Indeed, multiple studies have examined weight loss from bariatric surgery and its long-term effects on patients. Some of these studies, such as the Swedish Obese Subjects trial, found that bariatric surgery is associated with decreased mortality rates, possibly as a result of its beneficial effects on diabetes and other cardiovascular risk factors.
“Some of these studies were limited in that they didn’t have strongly matched comparison groups,” says Annemarie Hirsch, PhD, MPH, Assistant Professor, Department of Epidemiology and Health Services Research at Geisinger Health System. “Others concentrated on specific populations, like patients with Type 2 diabetes. We were really able to expand on these prior studies by looking at a long-term benefit from RYGB surgery in a broad patient population of those with and without Type 2 diabetes.”
Since 2004, Geisinger Health System has requested consent from its patients to collect EHR for research purposes. The patient consent rate at Geisinger is over 90 percent, which allows for the creation of large cohorts for studies. Almost 5,000 patients’ EHRs were examined for the study.
“A lot of our patients who receive bariatric surgery also receive care [in our healthcare system] for other reasons, specifically primary care,” Hirsch says.
“We were able to not only look at our bariatric surgery patients but also look at a tightly matched control group so we could really isolate the effect of surgery on cardiovascular outcomes and not worry too much about confounding data based on smoking habits or prior cardiovascular risks or things like that.”
The study, published in the Journal of the American Heart Association, found that patients who underwent RYGB surgery had a 45 percent reduced risk of a major cardiovascular event eight years after surgery. While heart attacks and strokes were lower after metabolic surgery, those numbers were not statistically significant. Driving the cardiovascular benefits was the decrease in the risk of congestive heart failure.
The findings have piqued the interest of other researchers.
“What was remarkable about the Geisinger Obesity Institute study was that patients had strong risk factors for developing heart failure over time,” says Philip Schauer, MD, Director of the Cleveland Clinic Bariatric and Metabolic Institute. “However, the group that had bariatric surgery had a much lower rate of developing congestive heart failure than the control group.”
While the results of the study are promising, the precise reasons for the lowered risk of heart failure due to bariatric surgery are uncertain.
“The study did not get into the mechanisms, but we do know that weight-loss surgery reduces cardiovascular risk factors like hypertension, hyperlipidemia and diabetes,” Dr. Benotti says. “Weight-loss surgery seems to have the ability to reverse the effects of obesity on the heart.”
Though weight loss itself plays a large role in the health benefits of bariatric surgery, past studies — such as one published in Surgical Endoscopy and Other Interventional Techniques, the official journal of the Society of American Gastrointestinal and Endoscopic Surgeons and European Association for Endoscopic Surgery — show positive effects on the body within weeks after a patient undergoes RYGB surgery.
“It may not just be the weight loss,” Hirsch says. “Changes in the body, such as a reduction in inflammation, can occur almost immediately after metabolic surgery. We know there’s an association between inflammation and cardiovascular risk, so this reduction of inflammation may be one of the protective effects of metabolic surgery.”
The Geisinger Obesity Institute plans to perform more research regarding bariatric surgery’s benefits.
“We’re actually doing a follow-up study examining the mechanisms of individuals before and after bariatric surgery with structural and heart imaging,” says Christopher Still, DO, Director of the Geisinger Obesity Research Institute. “If we can figure out the mechanisms of the benefits of bariatric surgery, hopefully we can correlate them with other therapeutic interventions.”