BALTIMORE – A staging scale developed by the bariatric team at the University of Alberta has shown potential as a tool to accurately predict major complications 1 year after Roux-en-Y gastric bypass (RYGB) surgery, surpassing the predictability of body mass index alone, a researcher reported at the annual meeting of the Society of American Gastrointestinal Endoscopic Surgeons.
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Researchers at the university validated the predictive utility of the scale, known as the Edmonton Obesity Staging System (EOSS), in a retrospective chart review of 378 patients who had RYGB between December 2009 and November 2015 at Royal Alexandra Hospital in Edmonton, Alt. The EOSS uses a scale from 0 to 4 to score a patient’s risk for complications: the higher the score, the greater the risk of complications.
“The EOSS may help determine risk of major complications after RYGB, and, given its overall simplicity, you can also think of it as analogous to the American Society of Anesthesiologists physical status classification system or the New York Heart Association classification system for congestive heart failure,” said Samuel Skulsky, a 3rd-year medical student at the University of Alberta. “It may have utility as well in communicating to patients their overall risk.”
A previous study applied the EOSS score to the National Health and Human Nutrition Examination Survey to compare it to use of body mass index (BMI) as a predictive marker of mortality (CMAJ. 2011;183:E1059-66). Where the four BMI classifications were clustered on the Kaplan-Meier between 0.7 and 0.9 at 200 months post examination, the four EOSS stages analyzed, 0-3, showed more of a spread, from around 0.55 for stage 3 to near 1.0 for stage 0. This gave the researchers the idea that EOSS could also be used to predict morbidity and mortality specifically in obese patients scheduled for surgery, Mr. Skulsky said. “With the Kaplan-Meier survival curves, the EOSS actually nicely stratifies the patients with their overall survival,” he said. “In comparison, BMI did not do as well in stratifying overall mortality.”
The study reported the following 1-year complication rates in the EOSS stages:
- Stage 0 (n = 14), 7.1%.
- Stage 1 (n = 41), 4.9%.
- Stage 2 (n = 297), 8.8%.
- Stage 3 (n = 26), 23.1%.
There were no stage 4 patients in the study population.