Comparability of weight loss reporting after gastric bypass and sleeve gastrectomy using BOLD data 2008-2011.

BACKGROUND: Weight loss after bariatric surgery is commonly reported as either a percentage of initial body weight (%IBW) or 100% minus %IBW which is a percentage of total weight loss (%TWL). These are basically equivalent expressions. Weight loss is also reported as %EWL or as a percentage of excess body mass index loss (%EBMIL). These last two expressions incorporate the concepts of ideal body weight and BMI = 25 as reference points. More straightforward but less commonly used is absolute weight loss. This study compares these various measures using the Bariatric Outcomes Longitudinal Database (BOLD). METHODS: BOLD data, 2008-2011, was accessed for outcomes on 239,659 gastric bypass (GB) and sleeve gastrectomy (SG) patients with approval of the Surgical Review Corporation. The outcome data was converted into %TWL, %EWL, and %EBMIL. %EBMIL was varied by changing the reference BMI from 1 to 25 kg/m(2). The post operation data was analyzed for both procedures. Variation coefficients (VC) were compared using different measurements on the same data pool. We assumed that the lesser the variation, the more reliable the measure is, and therefore, we made use of the VC to compare the different reporting methods. RESULTS: There were 164,247 patients who remained after removal of errors and missing data. Demographics are as follows: 78.1% female, 73.1% white, 12.5% black, 8.71% Hispanic, 81.6% GB, 18.4% SG, mean age of 44.8 years, height of 167.0 cm, weight of 132.0 kg, and BMI of 47.1 kg/m(2). GB patients had 26.8%TWL at 6 months (VC = 21.5) and 34.2%TWL at 12 months (VC = 27.0). %EWL was 54.7 at 6 months (VC = 27.3) and 69.4 at 12 months (VC = 30.9). Varying the reference BMI for %EBMIL showed the lowest VC to be 0-2 kg/m(2) for GB up to 12 months post operation. SG patients had 24.0%TWL at 6 months (VC = 25.4) and 29.5 at 12 months (VC = 30.5). %EWL was 50.0% at 6 months (VC = 31.4) and 60.2% at 12 months (VC = 34.5). Varying the reference BMI for %EBMIL showed that the lowest VC occurred when the reference weight was chosen as 0 kg/m(2) for both GB and SG. %TWL or, equivalently, %IBW had the lowest variation coefficient and therefore is the more accurate measure of weight loss following bariatric surgery. CONCLUSIONS: For ease and accuracy of comparison, the percentage of initial body weight or percentage of total weight loss should be used for the expression of weight loss after surgery.

A simpler method for predicting weight loss in the first year after Roux-en-Y gastric bypass.

Factors postulated to predict weight loss after gastric bypass surgery, include race, age, gender, technique, height, and initial weight. This paper contained 1551 gastric bypass patients (85.9% female). Operations were performed by one surgeon (MLO) at community hospitals in Southern California from 1989 to 2008 with 314 being laparoscopic and 1237 open. We created the following equation: In[percent weight] = At(2) - Bt, where t was the time after operation (days) and A and B are constants. Analysis was completed on R-software. The model fits with R(2) value 0.93 and gives patients a realistic mean target weight with a confidence interval of 95% for the first year. Conclusion. We created a curve predicting weight loss after surgery as a percentage of initial weight. Initial weight was the single most important predictor of weight loss after surgery. Other recorded variables accounted for less than 1% of variability. Unknown factors account for the remaining 6-7%.

Size really does matter-role of gastrojejunostomy in postoperative weight loss.

BACKGROUND: Although the published data have clearly related the size of the gastrojejunostomy anastomosis to the subsequent likelihood of a stricture, a correlation between the anastomosis size and postoperative weight loss has not previously been described. METHODS: A retrospective comparison was made of 124 anastomoses accomplished with the 21-mm circular stapler followed by 100 anastomoses created with the 45-mm linear stapler technique at 6 community hospitals in Southern California. Age, gender, and preoperative weights were not significantly different between the 2 groups. The precise size of the anastomosis created using the linear stapler technique could not be determined, but it was calculated to be slightly larger than a 25-mm circular stapled anastomosis. Both weight loss trends were fit with a 1-phase exponential nonlinear regression analysis. The resulting curves were compared using an F test. A 1-tailed t test was also used to compare the weight loss at 12 months. RESULTS: An F test comparison of the exponential weight loss curves generated by the 2 anastomosis groups showed a significantly different trend in weight loss (P <.001). A 1-tailed t test comparison of the 2 groups at 12 months revealed significantly different results (p <.0025). CONCLUSION: The results of this study show that the size of the anastomosis has a clear correlation with postoperative weight loss. A smaller opening results in significantly more weight loss.

Results of gastrojejunal anastomotic technique designed to reduce stricture.

BACKGROUND: The incidence of strictures developing after gastrojejunostomy has been reported to range from 3% to 31%. We found an unacceptably high stricture rate (13%) using a 21-mm circular stapler. Attempts to use the 25-mm circular stapler were frustrated by disparities between the size of the instrument and the patient's anatomy. We, therefore, modified the technique to accomplish the anastomosis with the linear stapler and hand sewing (LSA) at community hospitals in Southern California. METHODS: A total of 124 anastomoses were accomplished with the circular stapler (CSA) followed by 100 anastomoses using the LSA technique. Drains were used routinely with the CSA technique but were used only selectively with the LSA technique. Stricture was defined as that requiring endoscopic dilation for symptoms. Leaks were confirmed radiologically or surgically, and bleeding was defined as the need for transfusion. Our analysis used the Student t test and Fisher's exact test, with P <.05 considered statistically significant. RESULTS: No patient died. The LSA technique was faster and resulted in significantly fewer postoperative strictures and complications compared with the CSA technique. CONCLUSION: The results of our study have shown that the LSA technique, as described, is preferable to the CSA technique.