Five to 10 percent of surgically induced weight loss is associated with improved life expectancy and cardiovascular health compared with about 20 percent weight loss is necessary to observe similar benefits with a non-surgical treatment, according to researchers from Cleveland Clinic. In comparison. The findings also show that metabolic surgery may contribute health benefits that are independent of weight loss.
The paper, ‘How Much Weight Loss is Required for Cardiovascular Benefits? Insights From a Metabolic Surgery Matched-cohort Study’, published in the Annals of Surgery, sought to determine the minimum amount of weight loss required to see a reduction in major adverse cardiovascular events (MACE) as the minimum amount of weight loss to have a meaningful impact on cardiovascular health and survival is unknown.
The large, observational study examined 7,201 Cleveland Clinic patients: 1,223 patients with obesity and type 2 diabetes who underwent bariatric/metabolic surgery were matched to 5,978 patients who received usual medical care. About 80 percent of the patients had hypertension, 74 percent had dyslipidaemia and 31 percent were taking insulin to treat their diabetes.
Using different statistical models, the effects of weight loss were studied to identify the minimum weight loss needed to decrease the risk of death and of experiencing major adverse cardiovascular events, such as coronary artery events, cerebrovascular events, heart failure, kidney disease, and atrial fibrillation.
"Following metabolic surgery, the risk of death and major heart complications appears to decrease after about 5 percent and 10 percent weight loss, respectively,” said Dr Ali Aminian, director of Cleveland Clinic's Bariatric & Metabolic Institute and lead author of the study. “Whereas, in the nonsurgical group, both the risk of death and major cardiovascular complications decreased after losing approximately 20 percent of body weight.”
Researchers continue to study the physiological changes in the surgically modified gastrointestinal tract, the impact on hormone secretion and the microbiome. Those beneficial changes may contribute to the cardiovascular and survival benefits of metabolic surgery, independent of weight loss. More research is needed to better understand the underlying mechanisms for the health benefits of metabolic surgery in patients who have obesity and type 2 diabetes.
"This study suggests greater heart disease benefits are achieved with less weight loss following metabolic surgery than medical weight loss using lifestyle interventions,” said Dr Steven Nissen, Chief Academic Officer of the Heart, Vascular & Thoracic Institute at Cleveland Clinic, and the study's senior author. “The study findings suggest that there are important benefits of metabolic surgery independent of the weight loss achieved.”