STUDY ROUNDUP

Published in February 2015 Issue             


Association Between Bariatric Surgery and Long-term Survival (Journal of the American Medical Association)


Patients with obesity receiving care in the Veterans Affairs (VA) health system who had bariatric surgery, compared with matched control patients who did not have surgery, had lower all-cause mortality at five years and up to 10 years after surgery. A retrospective 14-year cohort study compared the all-cause mortality rate among 2,500 surgery patients (74% men) from 2000-2011 to 7,462 control pair matched for age, sex, geographic region, BMI and diabetes. Patients were on average 52 years old and had a BMI of 47. Bariatric procedures included gastric bypass (74%), sleeve gastrectomy (15%), adjustable gastric banding (10%) and
other (1%).


At 1 year, Kaplan-Meier estimated mortality rates were 2.4% for the surgical patients and 1.7% for the control participants. At 5 years, it was 6.4% for patients and 10.4% for control participants, and at 10 years, it was 13.8% for surgical patients and 23.9% for control participants. Adjusted analysis revealed no significant association between surgery and mortality after 1 year (adjusted hazard ratio, 1.28; 95% confidence interval [CI], 0.98 - 1.68) but significantly lower mortality by 5 years (adjusted hazard ratio, 0.45; 95% CI, 0.36 - 0.56) and between 5 and 14 years (adjusted hazard ratio, 0.47; 95% CI, 0.39 - 0.58). Surgery was associated with lower long-term mortality for both super obese (body mass index, >=50 kg/m2) patients and less obese (body mass index, <50 kg/m2) patients. The association with lower mortality was higher for patients with diabetes compared with those without diabetes.


Preoperative Factors and Three-Year Weight Change in the Longitudinal Assessment of Bariatric Surgery (LABS) Consortium (SOARD)


Percent weight change from baseline to three years in adults undergoing RYGB or LAGB between 2006 and 2009 were analyzed to evaluate the association between baseline factors and weight three-years post-op. The median age was 46 years for RYGB and 48 years for LAGB; 80% of RYGB participants and 75% of LAGB participants were female; and the median baseline BMI was 46 for RYGB and 44 for LAGB. The median weight loss three years following surgery for RYGB (n=1,513) was 31.5%, and 16.0% for LAGB (n=509). For RYGB, black participants lost 2.7% less weight compared to whites and participants with diabetes had 3.7% less weight loss at year 3 than those without diabetes. There were small, but statistically significant differences in weight change for RYGB in those with abnormal kidney function and current or recent smoking. For LAGB participants, those with a large band had 75% greater odds of experiencing less than 10% weight loss after adjusting for BMI and sex. The authors concluded that few baseline variables were associated with three-year weight change and the effects were small, so baseline variables have limited predictive value for weight loss following bariatric surgery.


Interest in Bariatric Surgery Among Obese Patients with Obstructive Sleep Apnea (SOARD)


Adult patients with low peri-operative risk and untreated severe obstructive sleep apnea (OSA) with a BMI of 35-45 kg/m2 were approached to participate in a informational visit about bariatric surgery as primary treatment for OSA. Of the 482 appropriate patients, over one-third (35.5%) were interested in bariatric surgery. Surgical interest was 47.2% in women vs. 27.6% in men and 67.3% in people with diabetes vs. 31.0% in with no diabetes. In multivariable adjusted models, female gender and diabetes remained highly predictive of bariatric surgery interest. Nearly two-thirds of patients with obesity and severe OSA are good candidates for bariatric surgery. Among candidates, over one-third are interested in this treatment. The results of this study indicate that metabolic improvements continue to be a major driver of surgery even in patients with severe OSA. Given patient interest, the role of bariatric surgery should be routinely discussed with OSA patients with obesity.


Inactivity More Deadly Than Obesity, Large New Study Finds (American Journal of Clinical Nutrition)


A cohort 12.4-year study in 334,161 European men and women examined if the risk of death resulting from excess adiposity could be lessened by physical activity (PA). Height, weight and waist circumference (WC) were measured, and PA was assessed with a validated self-report instrument. The combined associations between PA, BMI and WC with mortality were examined, stratified by center and age group, and adjusted for sex, education, smoking and alcohol intake. The hazards of all-cause mortality were reduced by 16–30% in moderately inactive individuals compared with those categorized as inactive in different strata of BMI and WC. Avoiding all inactivity would “theoretically” reduce all-cause mortality by 7.35%. The greatest reductions in mortality risk were observed between the two lowest activity groups across levels of general and abdominal adiposity, which suggests that efforts to encourage even small increases in activity may be beneficial to public health.