Roshni Venugopal, MD, Karina A Newhall, MD, Julia E Segal, BS, Thadeus L Trus, MD, William S Laycock. Dartmouth-Hitchcock Medical Center
Background: In the era of quality surveillance and measurement, reporting of clinical outcomes are not standardized. One of the most important reported measures in bariatric surgery is “Percent Excess Weight Loss” or %EWL, calculated from the difference between a patient’s “baseline weight” and “ideal body weight” or IBW.
Hypothesis: As bariatric programs determine when to identify the baseline weight of their patients, we expect this value is variable across programs. We hypothesize that lack of a standard definition for baseline weight can lead to significant differences in %EWL calculation. Our objective is to demonstrate this variability by utilizing different baseline weights to calculate %EWL in our patient subset.
Methods: A random sample of 60 patients was selected from bariatric patients who underwent laparoscopic Roux-n-Y gastric bypass or laparoscopic sleeve gastrectomy from January 2012 through December 2012 at Dartmouth-Hitchcock Medical Center. Patients lost to follow-up at 1 year and patients who became pregnant were excluded. %EWL at 1month and 1year was calculated using three baseline weights: first preoperative visit (PRE1), second preoperative visit (PRE2), and day of surgery (DOS). Paired t-tests were used to compare %EWL calculations at binary time points.
Results:
| Time after Surgery | %EWL PRE1 | %EWL PRE2 | %EWL DOS |
| 1 month | 23.70% | 22.02% | 15.17% |
| 1 year | 59.11% | 58.36% | 54.63% |
At 1 month: DOS versus PRE1 (p<0.0001); DOS versus PRE2 (p<0.001).
At 1 year: DOS versus PRE1 (p<0.0001); DOS versus PRE2 (p<0.0001).
Conclusion: Given the emerging need to compare and contrast clinical outcomes across geographic locations, amongst health care institutions, and between health care providers, it is important to standardize outcomes accounting methodology. We have shown that calculating %EWL within our patient sample using different baseline weights yields significantly different results. This reflects the variability that may occur from program to program. We advocate utilizing the earliest preoperative patient weight at entry into the clinical bariatric program as the baseline patient weight because we feel this will most accurately reflect the impact of interaction with a surgical weight loss program on clinical weight loss outcomes.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 80803
Program Number: P637
Presentation Session: Poster (Non CME)
Presentation Type: Poster
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