Obese adults have reduced risk for adverse CV outcomes after bariatric surgery
MedWire News: Obese adults who undergo bariatric surgery have a reduced risk for adverse cardiovascular (CV) outcomes, an analysis suggests.
These results, together with previously reported associations between bariatric surgery and long-term improvements in body weight, CV risk factors, quality of life, diabetes, cancer, and mortality, demonstrate that there are many benefits to bariatric surgery, write the authors.
Lars Sjöström (Sahlgrenska University Hospital, Gothenburg, Sweden) and colleagues analyzed data from the Swedish Obese Subjects study. This involved 2010 obese patients who underwent bariatric surgery and 2037 control individuals matched for 18 variables including weight, height, and diabetes. All patients were aged between 37 and 60 years, and had a body mass index (BMI) of at least 34 kg/m2 for men and 38 kg/m2 for women.
The surgery patients underwent gastric bypass (13.2%), banding (18.7%), or vertical banded gastroplasty (68.1%), while controls received standard care for obesity under the Swedish primary health care system, which ranged from advanced lifestyle advice at many sites to no treatment at other sites.
Patients who underwent bariatric surgery had a 53% lower risk for CV death than patients in the control group (p=0.002), at a rate of 28 events among 2010 patients versus 49 events among 2037 patients, respectively.
Patients who underwent bariatric surgery also had a 33% lower risk for first-time fatal or nonfatal CV events (including myocardial infarction or stroke, whichever came first) than those in the control group (p<0.001), at a rate of 199 events among 2010 patients versus 234 events among 2037 patients, respectively.
The surgical treatment benefit with respect to CV events was significantly associated with baseline plasma insulin (p<0.001 for interaction), with a greater treatment benefit seen in participants with higher insulin (>17.0 mU/L), at a hazard ratio for relative treatment effect of 0.69, than in patients with an insulin level of 17.0 mU/L or less, at a hazard ratio of 0.93.
In contrast, the surgical treatment benefit with respect to CV events was not significantly associated with baseline BMI or other metabolic variables.
"Our post hoc findings on relative and absolute treatment effects should be confirmed by prospective controlled trials specifically designed to study treatment effects on predefined end points," the authors write.
They acknowledge that it may take 10 years to obtain such results, and suggest that in the meantime, "clinical decisions must be based on best evidence available."
Edward Livingston (University of Texas Southwestern Medical Center, USA) cautions in a related commentary: "Because the expected health benefits do not necessarily exceed the risks of weight loss operations, obese patients without other weight-related complications generally should not undergo bariatric surgery."
MedWire (http://www.medwire-news.md/) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2012
By Piriya Mahendra