- Email: [email protected]
Preoperative weight loss is not a predictor of postoperative weight loss after laparoscopic Roux-en-Y gastric bypass
Surgery for Obesity and Related Diseases 4 (2008) 481– 485
Original article
Preoperative weight loss is not a predictor of postoperative weight loss after laparoscopic Roux-en-Y gastric bypass Arthur M. Carlin, M.D., Elizabeth A. O’Connor, M.D., Jeffrey A. Genaw, M.D., Sameeh Kawar, M.D. Department of Surgery, Henry Ford Hospital, Detroit, Michigan Received June 13, 2007; revised September 2, 2007; accepted September 11, 2007
Abstract
Background: Identification of preoperative predictors of weight loss after laparoscopic Roux-en-Y gastric bypass (LRYGB) can lead to improved clinical outcomes. The purpose of this study was to determine whether preoperative weight loss was associated with improved percentage of excess weight loss (%EWL) 1 year after LRYGB. Methods: A retrospective analysis was performed on the data from 295 patients who had undergone LRYGB at our institution from July 2004 to November 2005. Routine preoperative weight loss goals were implemented to facilitate the laparoscopic approach and ensure compliance with an appropriate nutritional and exercise program. Patients with an initial consultation BMI of ⬍50, 50 –59, and ⱖ60 kg/m2 were given weight loss goals of 5 lb and 5% and 10% of body weight, respectively. Results: The mean age was 45 ⫾ 10 years, and 89% were women and 70% were white. The mean BMI at the initial consultation was 51 ⫾ 7 kg/m2. A significant inverse correlation was found between the preoperative BMI and %EWL at 1 year postoperative (P ⬍.001). When controlling for BMI, no correlation was found between the %EWL and percentage of preoperative weight loss or attainment of the weight loss goals. The weight loss goals were met or surpassed by 79% of patients, and the mean %EWL at 1 year was 66%. Whites had greater %EWL at 1 year postoperatively compared with African Americans (67% versus 61%; P ⫽ .002). When controlling for age, gender, race, and consultation BMI, the preoperative weight loss did not predict for the %EWL at 1 year. Conclusion: The results of this study have shown that preoperative weight loss does not predict postoperative weight loss 1 year after LRYGB. A lower BMI, younger age, and white race predicted better %EWL. (Surg Obes Relat Dis 2008;4:481– 485.) © 2008 American Society for Metabolic and Bariatric Surgery. All rights reserved.
Keywords:
Gastric bypass; Preoperative weight loss; Percentage excess weight loss
A dramatic increase in bariatric surgery has occurred in the United States in the past decade [1]. This has been fueled by technological advancements in the field of laparoscopy and increased public awareness of the detrimental effects of morbid obesity on one’s health. Bariatric surgery has been shown to be the only effective method of treatment offering sustainable long-term weight loss in the morbidly Presented as a poster presentation at the 2007 Annual Meeting of the American Society for Bariatric Surgery, San Diego, California Reprints not available from the authors.
obese. The amount of postoperative weight loss is one of the important indicators of success after bariatric surgery; however, preoperative predictors of optimal weight loss remain elusive. Successful maintenance of weight loss is thought to correlate with appropriate dietary modifications and regular exercise. Therefore, some bariatric programs advocate preoperative weight loss as an indicator of the patient’s nutritional and exercise compliance in an effort to optimize the selection process for bariatric surgery. Preoperative weight loss has been demonstrated to decrease liver size [2]. It has been reported that patients with large steatotic livers have
1550-7289/08/$ – see front matter © 2008 American Society for Metabolic and Bariatric Surgery. All rights reserved. doi:10.1016/j.soard.2007.09.010
482
A. M. Carlin et al. / Surgery for Obesity and Related Diseases 4 (2008) 481– 485
increased operative complications and increased rates of conversion from laparoscopic to open gastric bypass [3]. Also, preoperative weight loss has been shown to reduce the operative time and decrease operative blood loss during laparoscopic Roux-en-Y gastric bypass (LRYGB) [4,5]. The significant improvements reported in the health of obese patients after dietary weight loss could improve the safety of bariatric surgery [6]. However, the value of preoperative weight loss before gastric bypass is controversial, and a paucity of data is available to support it. We have been advocates of preoperative weight loss for the reasons noted and to ensure that patients have a genuine appreciation of the essential postoperative lifestyle changes needed. We have included preoperative weight loss requirements since the inception of our bariatric surgery program. Thus, we were interested in the value of preoperative weight loss as a predictor of postoperative weight loss 1 year after LRYGB. Our hypothesis was that greater preoperative weight loss or the attainment of a weight loss goal would predict for better patient compliance with postoperative nutrition and exercise and ultimately a greater %EWL 1 year after LRYGB. Methods A retrospective analysis was performed on the data of 295 morbidly obese patients who had undergone LRYGB at our institution from July 2004 to November 2005 and who had complete documentation of the consultation, preoperative, and 1-year postoperative weights. Only patients with complete documentation were included in this study; thus, by design, the 1-year follow-up was 100%. All patients met the 1991 National Institutes of Health consensus guidelines for bariatric surgery [7]. Routine preoperative weight loss goals were implemented to facilitate the laparoscopic approach and ensure compliance with an appropriate nutritional and exercise regimen. All patients were counseled by an exercise physiologist, who defined an individually tailored exercise program, and by a registered dietician, who described the preferred nutritional guidelines, although any previously successful dietary method for weight loss was allowed. If patients did not meet their weight loss goals but had documented adherence to an appropriate nutritional and exercise regimen, with some corresponding weight loss, LRYGB was scheduled. Patients with a BMI at initial consultation of ⬍50, 50 –59, and ⱖ60 kg/m2 were given a weight loss goal of 5 lb, 5% of body weight, and 10% of body weight, respectively. The information recorded for each patient included age, gender, race, height, weight at the initial consultation, weight loss goal, weight at the final reevaluation for surgical scheduling, preoperative weight, 1-year postoperative weight, exercise regimen, and percentage of excess weight loss (%EWL). The postoperative %EWL was calculated at 1 year after surgery using the immediate preoperative weight, except as specified in Table 1. LRYGB was performed by either 1 of 2 bariatric sur-
Table 1 BMI correlated with %EWL at 1 year BMI (kg/m2) At initial consultation ⬍50 50–60 ⱖ60 Preoperatively ⬍50 50–60 ⱖ60
n 152 120 23 213 73 9
%EWL at 1 yr
P value
From initial consultation weight 72 ⫾ 15 66 ⫾ 12 63 ⫾ 14 From preoperative weight 68 ⫾ 16 60 ⫾ 14 57 ⫾ 15
.001
.001
BMI ⫽ body mass index; %EWL ⫽ percentage of excess weight loss.
geons (A.M.C. or J.A.G.) and was standardized, with an isolated, vertical, lesser curve– based, small-volume (ⱕ20 cm3) gastric pouch, an 11-mm handsewn gastrojejunostomy, and a Roux limb of 100 cm. Our institutional review board approved the project and data processing. Data are expressed as the mean ⫾ standard deviation. Analysis of variance was performed to determine the correlation between the BMI groups and %EWL at 1 year postoperatively. The significance of difference in the continuous variables between groups was determined by Student’s t test and logistic regression analysis. Differences between qualitative variables were determined using chisquare analysis. Multivariate linear regression analysis was used to determine the independent predictors of the %EWL. Statistical analysis was performed with JMP, version 6.0.0, statistical software (SAS Institute, Cary, NC). Statistical significance was set at P ⬍.05. Results The mean patient age was 45 ⫾ 10 years (range 20 – 67). Of the 295 patients, 261 were women (89%); 207 were white (70%), 77 were African American, and 11 were another race/ethnicity. The mean BMI at the initial consultation was 51 ⫾ 7 kg/m2 (range 36 – 88). After completion of the weight loss before surgery, the mean preoperative BMI had decreased to 48 ⫾ 6 kg/m2 (range 33–77). A significant inverse correlation was found between the preoperative BMI and the %EWL at 1 year postoperatively (P ⬍.001; Fig. 1). Additionally, patients in the lower BMI groups had a significantly greater %EWL (Table 1). As dictated by our protocol, patients in the greater BMI groups had significantly greater preoperative weight loss. Those with a consultation BMI of ⬍50, 50 –59, and ⱖ60 kg/m2, had a mean 4%, 6%, and 9% preoperative weight loss, respectively (P ⬍.001). When controlling for BMI group, no correlation was found between the percentage of preoperative weight loss and the postoperative %EWL at 1 year. The patients’ self-reported exercise regimen (times/wk) did not predict for postoperative weight loss. The overall mean %EWL at 1 year postoperatively, calculated from the initial consultation and preoperative weights were 69% and 66%, respectively.
A. M. Carlin et al. / Surgery for Obesity and Related Diseases 4 (2008) 481– 485
Fig. 1. Preoperative BMI correlated with %EWL at 1 year postoperatively (r ⫽ ⫺.3544277; P ⬍.001).
The preoperative weight loss goals were met or surpassed by 52% at the final reevaluation (weight when surgery was scheduled) and by 79% preoperatively. The 62 patients who did not meet their weight loss goals preoperatively achieved a mean of 66% of their goal. The attainment of weight loss goals was not dependent on age, race, or gender. The attainment of weight loss goals did not have a significant effect on the %EWL 1 year after LRYGB (Table 2). Even if patients attained 150% of their weight loss goal, no significant difference was found in the %EWL at 1 year when corrected for BMI group. The BMI groups were similar relative to age and race; however, a greater percentage of patients in the lower BMI groups were women. Gender did not correlate with the %EWL. In patients with a BMI of ⬍60 kg/m2, a significant inverse correlation was found between age and the %EWL (r ⫽ ⫺.131; P ⫽ .031). Whites had a significantly greater %EWL at 1 year postoperatively compared with African Americans (67% versus 61%, P ⫽ .002), despite no difference in BMI, preoperative weight loss, or self-reported exercise. When controlling for age, gender, race, and initial BMI, the percentage of preoperative weight loss did not predict for %EWL at 1 year; the only independent predictors of a greater %EWL were younger age, white race, and lower consultation BMI. Discussion Although some bariatric surgeons ascribe to the potential beneficial effects of preoperative weight loss, very little data are available to support it. We have been advocates of this preoperative requirement in an effort to motivate patients to comply with the essential nutritional and exercise regimens and to optimize the outcomes of LRYGB through a reduction in liver size and overall health improvements. Addi-
483
tionally, we believed that patients who achieved their preoperative weight loss goals would have a greater %EWL because of better compliance. Our data have not supported this hypothesis, because no correlation between the amount of preoperative weight loss and the %EWL at 1 year postoperatively was identified when controlling for BMI. We have shown that patients with a greater preoperative BMI had a significantly lower %EWL 1 year after LRYGB. This relationship has been demonstrated previously, and the BMI appears to be the most consistent predictor of postoperative excess weight loss [8 –10]. Therefore, any evaluation of postoperative weight loss must control for BMI. Our data were controlled for BMI on multivariate linear regression analysis and analyzed by division into 3 BMI groups: BMI ⬍50, 50 – 60, and ⱖ60 kg/m2. A study by Alvarado et al. [10] identified a 1.8% increase in the %EWL 1 year after LRYGB with each 1% increase of preoperative weight loss. Although Alvarado et al. [10] controlled for age, gender, and co-morbidities, there was no apparent accounting for BMI. In their bariatric program, all patients were given a 10% preoperative weight loss goal, but only 18% of their patients achieved this goal. This is in contrast to our data in which the weight loss goals were stratified by BMI, and 79% achieved their goal. Only 1 prospective randomized trial has been published of LRYGB patients designed to assess the effect of preoperative weight loss on the %EWL [4]. Alami et al. [4] randomized patients at the initial contact into two groups: a preoperative weight loss group and a preoperative nonweight loss group. The weight loss group was required to demonstrate a 10% weight loss before surgery. Although the weight loss group had attained a significantly greater %EWL 3 months after LRYGB (44% versus 33%), no significant difference was found in the %EWL 6 months postoperatively between the weight loss group (54%) and nonweight loss group (51%). Although the study was underpowered, and a type II error might have been present, their results at 6 months support our findings. Table 2 Consultation BMI correlated with attainment of weight loss goal and %EWL Consultation BMI (kg/m2)
n
⬍50
152
50–60
ⱖ60
Preoperative weight loss goal met
Mean weight loss goal met (%)
Postoperative %EWL at 1 yr
No Yes
32 120
No Yes
52 218
70 70
No Yes
26 94
No Yes
83 156
61 63
No Yes
3 20
No Yes
87 128
47 58
P value
.997
120
.585
23
.273
Abbreviations as in Table 1.
484
A. M. Carlin et al. / Surgery for Obesity and Related Diseases 4 (2008) 481– 485
Two other reports evaluating preoperative weight loss in patients undergoing LRYGB have confirmed our results [11,12]. van de Weijgert et al. [11] proceeded with gastric bypass only after patients lost 50% of their excess weight. Even with this extensive preoperative weight loss requirement, the %EWL after gastric bypass in their patients was not enhanced compared with other published weight loss outcomes after gastric bypass. Martin et al. [12] found that a preoperative weight loss program was practical and safe. Their group demonstrated no difference in weight loss after gastric bypass between the successful preoperative dieters (⬎7.5 kg weight loss) and the nondieters, but the successful dieters were significantly heavier and had more psychopathologic features. Certain psychosocial and behavioral factors might be more important for optimal weight loss after LRYGB, but these are somewhat difficult to discern, because their influence might be indirect and subtle. Reviewing questionnaire information, Ray et al. [13] found that intrinsic motivational factors appeared to predict for greater weight loss after gastric bypass. In addition to the actual percentage of preoperative weight loss achieved, we compared the patients who met their weight loss goal with those who did not meet their goal. Again, we found no difference in the %EWL after LRYGB. It could be that having a preoperative weight loss goal and working toward it is a behavior that only triggers a transient motivational improvement in morbidly obese patients. Additionally, Jamal et al. [14] found that insurancemandated preoperative dietary counseling does not improve outcomes after gastric bypass. Not only was the surgical dropout rate 50% greater in patients with a mandatory 13 weeks of preoperative dietary counseling, but the %EWL 1 year after gastric bypass was lower compared with patients without this prerequisite [14]. Thus, postoperative compliance, as measured by the %EWL, is not enhanced by preoperative weight loss or insurance-mandated preoperative dietary counseling. With multivariate linear regression analysis, we identified three independent predictors of %EWL: lower preoperative BMI, younger age, and white race. Ma et al. [15] also identified younger age and lower baseline weight as predictors of weight loss after LRYGB. The race disparity we identified further supports our results that preoperative weight loss does not predict for postoperative weight loss. The whites and African Americans had similar preoperative BMIs and preoperative weight loss, yet the whites had a significantly greater %EWL 1 year after LRYGB. Others have shown that African Americans experience significantly less weight loss after gastric bypass, and this could be related to differences in eating patterns, genetic variability, or other, as yet unidentified, etiologies [16]. To our knowledge, the present report is the largest evaluation in the small collection of studies assessing the effects of preoperative weight loss on the %EWL after LRYGB. One of the limitations of this report was the retrospective design, although all patients included in this analysis had
complete documentation of the consultation, preoperative, and 1-year postoperative weights. Because all our patients were given weight loss goals, with 72% meeting their goal and the others achieving 66% of their goal, we could not provide comparative data on patients without preoperative weight loss. Also, other potential factors that have been identified as negatively affecting weight loss with gastric bypass were not collected in this study, including the presence of diabetes, support group nonattendance, and married status [15,17,18].
Conclusion The results of our study have indicated that a lower initial BMI, younger age, and white race all predict for a better postoperative %EWL 1 year after LRYGB. The amount of preoperative weight loss was not a predictor of postoperative weight loss. Additionally, the achievement of a preoperative weight loss goal did not improve postoperative weight loss. Because the %EWL after LRYGB was not dependent on the percentage of preoperative weight loss, any preoperative weight loss appears to be additive to the postoperative weight loss. Additional study in a randomized fashion is warranted.
Disclosures The authors claim no commercial associations that might be a conflict of interest in relation to this article.
References [1] Steinbrook R. Surgery for severe obesity. N Engl J Med 2004;350: 1075–9. [2] Fris RJ. Preoperative low energy diet diminishes liver size. Obes Surg 2004;14:1165–70. [3] Schwartz ML, Drew RL, Chazin-Caldie M. Laparoscopic Roux-en-Y: preoperative determinants of prolonged operative times, conversion to open gastric bypasses, and postoperative complications. Obes Surg 2003;12:734 – 8. [4] Alami RS, Morton JM, Schuster R, et al. Is there a benefit to preoperative weight loss in gastric bypass patients? A prospective randomized trial. Surg Obes Relat Dis 2007;3:141–5. [5] Liu RC, Sabnis AA, Forsyth C, Chand B. The effects of acute preoperative weight loss on laparoscopic Roux-en-Y gastric bypass. Obes Surg 2005;15:1396 – 402. [6] Hong K, Li Z, Wang HJ, Elashoff R, Heber D. Analysis of weight loss outcomes using VLCD in black and white overweight and obese women with and without metabolic syndrome. Int J Obes 2005;29:436 – 42. [7] National Institutes of Health Consensus Development Panel. Gastrointestinal surgery for obesity: National Institutes of Health consensus development conference draft statement. Obes Surg 1991;1:257– 66. [8] Halverson JD, Koehler RE. Gastric bypass: analysis of weight loss and factors determining success. Surgery 1981;90:446 –55. [9] Vallis TM, Ross MA. The role of psychological factors in bariatric surgery for morbid obesity: identification of psychological predictors of success. Obes Surg 1993;3:346 –59.
A. M. Carlin et al. / Surgery for Obesity and Related Diseases 4 (2008) 481– 485 [10] Alvarado R, Alami RS, Hsu G, et al. The impact of preoperative weight loss in patients undergoing laparoscopic Roux-en-Y gastric bypass. Obes Surg 2005;15:1282– 6. [11] van de Weijgert EJHM, Ruseler CH, Eite JWF. Long-term follow-up after gastric surgery for morbid obesity: preoperative weight loss improves the long-term control of morbid obesity after vertical banded gastroplasty. Obes Surg 1999;9:426 –32. [12] Martin LF, Tan TL, Holmes PA, Becker DA, Horn J, Bixler EO. Can morbidly obese patients safely lose weight preoperatively? Am J Surg 1995;169:245–53. [13] Ray EC, Nickels MW, Sayeed S, Sax HC. Predicting success after gastric bypass: the role of psychosocial and behavioral factors. Surgery 2003;134:555– 63.
485
[14] Jamal MK, DeMaria EJ, Johnson JM, et al. Insurance-mandated preoperative dietary counseling does not improve outcome and increased dropout rates in patients considering gastric bypass surgery for morbid obesity. Surg Obes Relat Dis 2006;2:122–7. [15] Ma Y, Pagoto SL, Olendzki BC, et al. Predictors of weight status following laparoscopic gastric bypass. Obes Surg 2006;16:1227–31. [16] Sugerman HJ. Bariatric surgery for severe obesity. J Assoc Acad Minor Phys 2001;12:129 –36. [17] Hildebrandt S. Effects of participation in bariatric support group after Roux-en-Y gastric bypass. Obes Surg 1998;8:535– 42. [18] Lutfi R, Torquati A, Sekhar N, Richards WO. Predictors of success after laparoscopic gastric bypass: a multivariate analysis of socioeconomic factors. Surg Endosc 2006;20:864 –7.
Original article
Preoperative weight loss is not a predictor of postoperative weight loss after laparoscopic Roux-en-Y gastric bypass Arthur M. Carlin, M.D., Elizabeth A. O’Connor, M.D., Jeffrey A. Genaw, M.D., Sameeh Kawar, M.D. Department of Surgery, Henry Ford Hospital, Detroit, Michigan Received June 13, 2007; revised September 2, 2007; accepted September 11, 2007
Abstract
Background: Identification of preoperative predictors of weight loss after laparoscopic Roux-en-Y gastric bypass (LRYGB) can lead to improved clinical outcomes. The purpose of this study was to determine whether preoperative weight loss was associated with improved percentage of excess weight loss (%EWL) 1 year after LRYGB. Methods: A retrospective analysis was performed on the data from 295 patients who had undergone LRYGB at our institution from July 2004 to November 2005. Routine preoperative weight loss goals were implemented to facilitate the laparoscopic approach and ensure compliance with an appropriate nutritional and exercise program. Patients with an initial consultation BMI of ⬍50, 50 –59, and ⱖ60 kg/m2 were given weight loss goals of 5 lb and 5% and 10% of body weight, respectively. Results: The mean age was 45 ⫾ 10 years, and 89% were women and 70% were white. The mean BMI at the initial consultation was 51 ⫾ 7 kg/m2. A significant inverse correlation was found between the preoperative BMI and %EWL at 1 year postoperative (P ⬍.001). When controlling for BMI, no correlation was found between the %EWL and percentage of preoperative weight loss or attainment of the weight loss goals. The weight loss goals were met or surpassed by 79% of patients, and the mean %EWL at 1 year was 66%. Whites had greater %EWL at 1 year postoperatively compared with African Americans (67% versus 61%; P ⫽ .002). When controlling for age, gender, race, and consultation BMI, the preoperative weight loss did not predict for the %EWL at 1 year. Conclusion: The results of this study have shown that preoperative weight loss does not predict postoperative weight loss 1 year after LRYGB. A lower BMI, younger age, and white race predicted better %EWL. (Surg Obes Relat Dis 2008;4:481– 485.) © 2008 American Society for Metabolic and Bariatric Surgery. All rights reserved.
Keywords:
Gastric bypass; Preoperative weight loss; Percentage excess weight loss
A dramatic increase in bariatric surgery has occurred in the United States in the past decade [1]. This has been fueled by technological advancements in the field of laparoscopy and increased public awareness of the detrimental effects of morbid obesity on one’s health. Bariatric surgery has been shown to be the only effective method of treatment offering sustainable long-term weight loss in the morbidly Presented as a poster presentation at the 2007 Annual Meeting of the American Society for Bariatric Surgery, San Diego, California Reprints not available from the authors.
obese. The amount of postoperative weight loss is one of the important indicators of success after bariatric surgery; however, preoperative predictors of optimal weight loss remain elusive. Successful maintenance of weight loss is thought to correlate with appropriate dietary modifications and regular exercise. Therefore, some bariatric programs advocate preoperative weight loss as an indicator of the patient’s nutritional and exercise compliance in an effort to optimize the selection process for bariatric surgery. Preoperative weight loss has been demonstrated to decrease liver size [2]. It has been reported that patients with large steatotic livers have
1550-7289/08/$ – see front matter © 2008 American Society for Metabolic and Bariatric Surgery. All rights reserved. doi:10.1016/j.soard.2007.09.010
482
A. M. Carlin et al. / Surgery for Obesity and Related Diseases 4 (2008) 481– 485
increased operative complications and increased rates of conversion from laparoscopic to open gastric bypass [3]. Also, preoperative weight loss has been shown to reduce the operative time and decrease operative blood loss during laparoscopic Roux-en-Y gastric bypass (LRYGB) [4,5]. The significant improvements reported in the health of obese patients after dietary weight loss could improve the safety of bariatric surgery [6]. However, the value of preoperative weight loss before gastric bypass is controversial, and a paucity of data is available to support it. We have been advocates of preoperative weight loss for the reasons noted and to ensure that patients have a genuine appreciation of the essential postoperative lifestyle changes needed. We have included preoperative weight loss requirements since the inception of our bariatric surgery program. Thus, we were interested in the value of preoperative weight loss as a predictor of postoperative weight loss 1 year after LRYGB. Our hypothesis was that greater preoperative weight loss or the attainment of a weight loss goal would predict for better patient compliance with postoperative nutrition and exercise and ultimately a greater %EWL 1 year after LRYGB. Methods A retrospective analysis was performed on the data of 295 morbidly obese patients who had undergone LRYGB at our institution from July 2004 to November 2005 and who had complete documentation of the consultation, preoperative, and 1-year postoperative weights. Only patients with complete documentation were included in this study; thus, by design, the 1-year follow-up was 100%. All patients met the 1991 National Institutes of Health consensus guidelines for bariatric surgery [7]. Routine preoperative weight loss goals were implemented to facilitate the laparoscopic approach and ensure compliance with an appropriate nutritional and exercise regimen. All patients were counseled by an exercise physiologist, who defined an individually tailored exercise program, and by a registered dietician, who described the preferred nutritional guidelines, although any previously successful dietary method for weight loss was allowed. If patients did not meet their weight loss goals but had documented adherence to an appropriate nutritional and exercise regimen, with some corresponding weight loss, LRYGB was scheduled. Patients with a BMI at initial consultation of ⬍50, 50 –59, and ⱖ60 kg/m2 were given a weight loss goal of 5 lb, 5% of body weight, and 10% of body weight, respectively. The information recorded for each patient included age, gender, race, height, weight at the initial consultation, weight loss goal, weight at the final reevaluation for surgical scheduling, preoperative weight, 1-year postoperative weight, exercise regimen, and percentage of excess weight loss (%EWL). The postoperative %EWL was calculated at 1 year after surgery using the immediate preoperative weight, except as specified in Table 1. LRYGB was performed by either 1 of 2 bariatric sur-
Table 1 BMI correlated with %EWL at 1 year BMI (kg/m2) At initial consultation ⬍50 50–60 ⱖ60 Preoperatively ⬍50 50–60 ⱖ60
n 152 120 23 213 73 9
%EWL at 1 yr
P value
From initial consultation weight 72 ⫾ 15 66 ⫾ 12 63 ⫾ 14 From preoperative weight 68 ⫾ 16 60 ⫾ 14 57 ⫾ 15
.001
.001
BMI ⫽ body mass index; %EWL ⫽ percentage of excess weight loss.
geons (A.M.C. or J.A.G.) and was standardized, with an isolated, vertical, lesser curve– based, small-volume (ⱕ20 cm3) gastric pouch, an 11-mm handsewn gastrojejunostomy, and a Roux limb of 100 cm. Our institutional review board approved the project and data processing. Data are expressed as the mean ⫾ standard deviation. Analysis of variance was performed to determine the correlation between the BMI groups and %EWL at 1 year postoperatively. The significance of difference in the continuous variables between groups was determined by Student’s t test and logistic regression analysis. Differences between qualitative variables were determined using chisquare analysis. Multivariate linear regression analysis was used to determine the independent predictors of the %EWL. Statistical analysis was performed with JMP, version 6.0.0, statistical software (SAS Institute, Cary, NC). Statistical significance was set at P ⬍.05. Results The mean patient age was 45 ⫾ 10 years (range 20 – 67). Of the 295 patients, 261 were women (89%); 207 were white (70%), 77 were African American, and 11 were another race/ethnicity. The mean BMI at the initial consultation was 51 ⫾ 7 kg/m2 (range 36 – 88). After completion of the weight loss before surgery, the mean preoperative BMI had decreased to 48 ⫾ 6 kg/m2 (range 33–77). A significant inverse correlation was found between the preoperative BMI and the %EWL at 1 year postoperatively (P ⬍.001; Fig. 1). Additionally, patients in the lower BMI groups had a significantly greater %EWL (Table 1). As dictated by our protocol, patients in the greater BMI groups had significantly greater preoperative weight loss. Those with a consultation BMI of ⬍50, 50 –59, and ⱖ60 kg/m2, had a mean 4%, 6%, and 9% preoperative weight loss, respectively (P ⬍.001). When controlling for BMI group, no correlation was found between the percentage of preoperative weight loss and the postoperative %EWL at 1 year. The patients’ self-reported exercise regimen (times/wk) did not predict for postoperative weight loss. The overall mean %EWL at 1 year postoperatively, calculated from the initial consultation and preoperative weights were 69% and 66%, respectively.
A. M. Carlin et al. / Surgery for Obesity and Related Diseases 4 (2008) 481– 485
Fig. 1. Preoperative BMI correlated with %EWL at 1 year postoperatively (r ⫽ ⫺.3544277; P ⬍.001).
The preoperative weight loss goals were met or surpassed by 52% at the final reevaluation (weight when surgery was scheduled) and by 79% preoperatively. The 62 patients who did not meet their weight loss goals preoperatively achieved a mean of 66% of their goal. The attainment of weight loss goals was not dependent on age, race, or gender. The attainment of weight loss goals did not have a significant effect on the %EWL 1 year after LRYGB (Table 2). Even if patients attained 150% of their weight loss goal, no significant difference was found in the %EWL at 1 year when corrected for BMI group. The BMI groups were similar relative to age and race; however, a greater percentage of patients in the lower BMI groups were women. Gender did not correlate with the %EWL. In patients with a BMI of ⬍60 kg/m2, a significant inverse correlation was found between age and the %EWL (r ⫽ ⫺.131; P ⫽ .031). Whites had a significantly greater %EWL at 1 year postoperatively compared with African Americans (67% versus 61%, P ⫽ .002), despite no difference in BMI, preoperative weight loss, or self-reported exercise. When controlling for age, gender, race, and initial BMI, the percentage of preoperative weight loss did not predict for %EWL at 1 year; the only independent predictors of a greater %EWL were younger age, white race, and lower consultation BMI. Discussion Although some bariatric surgeons ascribe to the potential beneficial effects of preoperative weight loss, very little data are available to support it. We have been advocates of this preoperative requirement in an effort to motivate patients to comply with the essential nutritional and exercise regimens and to optimize the outcomes of LRYGB through a reduction in liver size and overall health improvements. Addi-
483
tionally, we believed that patients who achieved their preoperative weight loss goals would have a greater %EWL because of better compliance. Our data have not supported this hypothesis, because no correlation between the amount of preoperative weight loss and the %EWL at 1 year postoperatively was identified when controlling for BMI. We have shown that patients with a greater preoperative BMI had a significantly lower %EWL 1 year after LRYGB. This relationship has been demonstrated previously, and the BMI appears to be the most consistent predictor of postoperative excess weight loss [8 –10]. Therefore, any evaluation of postoperative weight loss must control for BMI. Our data were controlled for BMI on multivariate linear regression analysis and analyzed by division into 3 BMI groups: BMI ⬍50, 50 – 60, and ⱖ60 kg/m2. A study by Alvarado et al. [10] identified a 1.8% increase in the %EWL 1 year after LRYGB with each 1% increase of preoperative weight loss. Although Alvarado et al. [10] controlled for age, gender, and co-morbidities, there was no apparent accounting for BMI. In their bariatric program, all patients were given a 10% preoperative weight loss goal, but only 18% of their patients achieved this goal. This is in contrast to our data in which the weight loss goals were stratified by BMI, and 79% achieved their goal. Only 1 prospective randomized trial has been published of LRYGB patients designed to assess the effect of preoperative weight loss on the %EWL [4]. Alami et al. [4] randomized patients at the initial contact into two groups: a preoperative weight loss group and a preoperative nonweight loss group. The weight loss group was required to demonstrate a 10% weight loss before surgery. Although the weight loss group had attained a significantly greater %EWL 3 months after LRYGB (44% versus 33%), no significant difference was found in the %EWL 6 months postoperatively between the weight loss group (54%) and nonweight loss group (51%). Although the study was underpowered, and a type II error might have been present, their results at 6 months support our findings. Table 2 Consultation BMI correlated with attainment of weight loss goal and %EWL Consultation BMI (kg/m2)
n
⬍50
152
50–60
ⱖ60
Preoperative weight loss goal met
Mean weight loss goal met (%)
Postoperative %EWL at 1 yr
No Yes
32 120
No Yes
52 218
70 70
No Yes
26 94
No Yes
83 156
61 63
No Yes
3 20
No Yes
87 128
47 58
P value
.997
120
.585
23
.273
Abbreviations as in Table 1.
484
A. M. Carlin et al. / Surgery for Obesity and Related Diseases 4 (2008) 481– 485
Two other reports evaluating preoperative weight loss in patients undergoing LRYGB have confirmed our results [11,12]. van de Weijgert et al. [11] proceeded with gastric bypass only after patients lost 50% of their excess weight. Even with this extensive preoperative weight loss requirement, the %EWL after gastric bypass in their patients was not enhanced compared with other published weight loss outcomes after gastric bypass. Martin et al. [12] found that a preoperative weight loss program was practical and safe. Their group demonstrated no difference in weight loss after gastric bypass between the successful preoperative dieters (⬎7.5 kg weight loss) and the nondieters, but the successful dieters were significantly heavier and had more psychopathologic features. Certain psychosocial and behavioral factors might be more important for optimal weight loss after LRYGB, but these are somewhat difficult to discern, because their influence might be indirect and subtle. Reviewing questionnaire information, Ray et al. [13] found that intrinsic motivational factors appeared to predict for greater weight loss after gastric bypass. In addition to the actual percentage of preoperative weight loss achieved, we compared the patients who met their weight loss goal with those who did not meet their goal. Again, we found no difference in the %EWL after LRYGB. It could be that having a preoperative weight loss goal and working toward it is a behavior that only triggers a transient motivational improvement in morbidly obese patients. Additionally, Jamal et al. [14] found that insurancemandated preoperative dietary counseling does not improve outcomes after gastric bypass. Not only was the surgical dropout rate 50% greater in patients with a mandatory 13 weeks of preoperative dietary counseling, but the %EWL 1 year after gastric bypass was lower compared with patients without this prerequisite [14]. Thus, postoperative compliance, as measured by the %EWL, is not enhanced by preoperative weight loss or insurance-mandated preoperative dietary counseling. With multivariate linear regression analysis, we identified three independent predictors of %EWL: lower preoperative BMI, younger age, and white race. Ma et al. [15] also identified younger age and lower baseline weight as predictors of weight loss after LRYGB. The race disparity we identified further supports our results that preoperative weight loss does not predict for postoperative weight loss. The whites and African Americans had similar preoperative BMIs and preoperative weight loss, yet the whites had a significantly greater %EWL 1 year after LRYGB. Others have shown that African Americans experience significantly less weight loss after gastric bypass, and this could be related to differences in eating patterns, genetic variability, or other, as yet unidentified, etiologies [16]. To our knowledge, the present report is the largest evaluation in the small collection of studies assessing the effects of preoperative weight loss on the %EWL after LRYGB. One of the limitations of this report was the retrospective design, although all patients included in this analysis had
complete documentation of the consultation, preoperative, and 1-year postoperative weights. Because all our patients were given weight loss goals, with 72% meeting their goal and the others achieving 66% of their goal, we could not provide comparative data on patients without preoperative weight loss. Also, other potential factors that have been identified as negatively affecting weight loss with gastric bypass were not collected in this study, including the presence of diabetes, support group nonattendance, and married status [15,17,18].
Conclusion The results of our study have indicated that a lower initial BMI, younger age, and white race all predict for a better postoperative %EWL 1 year after LRYGB. The amount of preoperative weight loss was not a predictor of postoperative weight loss. Additionally, the achievement of a preoperative weight loss goal did not improve postoperative weight loss. Because the %EWL after LRYGB was not dependent on the percentage of preoperative weight loss, any preoperative weight loss appears to be additive to the postoperative weight loss. Additional study in a randomized fashion is warranted.
Disclosures The authors claim no commercial associations that might be a conflict of interest in relation to this article.
References [1] Steinbrook R. Surgery for severe obesity. N Engl J Med 2004;350: 1075–9. [2] Fris RJ. Preoperative low energy diet diminishes liver size. Obes Surg 2004;14:1165–70. [3] Schwartz ML, Drew RL, Chazin-Caldie M. Laparoscopic Roux-en-Y: preoperative determinants of prolonged operative times, conversion to open gastric bypasses, and postoperative complications. Obes Surg 2003;12:734 – 8. [4] Alami RS, Morton JM, Schuster R, et al. Is there a benefit to preoperative weight loss in gastric bypass patients? A prospective randomized trial. Surg Obes Relat Dis 2007;3:141–5. [5] Liu RC, Sabnis AA, Forsyth C, Chand B. The effects of acute preoperative weight loss on laparoscopic Roux-en-Y gastric bypass. Obes Surg 2005;15:1396 – 402. [6] Hong K, Li Z, Wang HJ, Elashoff R, Heber D. Analysis of weight loss outcomes using VLCD in black and white overweight and obese women with and without metabolic syndrome. Int J Obes 2005;29:436 – 42. [7] National Institutes of Health Consensus Development Panel. Gastrointestinal surgery for obesity: National Institutes of Health consensus development conference draft statement. Obes Surg 1991;1:257– 66. [8] Halverson JD, Koehler RE. Gastric bypass: analysis of weight loss and factors determining success. Surgery 1981;90:446 –55. [9] Vallis TM, Ross MA. The role of psychological factors in bariatric surgery for morbid obesity: identification of psychological predictors of success. Obes Surg 1993;3:346 –59.
A. M. Carlin et al. / Surgery for Obesity and Related Diseases 4 (2008) 481– 485 [10] Alvarado R, Alami RS, Hsu G, et al. The impact of preoperative weight loss in patients undergoing laparoscopic Roux-en-Y gastric bypass. Obes Surg 2005;15:1282– 6. [11] van de Weijgert EJHM, Ruseler CH, Eite JWF. Long-term follow-up after gastric surgery for morbid obesity: preoperative weight loss improves the long-term control of morbid obesity after vertical banded gastroplasty. Obes Surg 1999;9:426 –32. [12] Martin LF, Tan TL, Holmes PA, Becker DA, Horn J, Bixler EO. Can morbidly obese patients safely lose weight preoperatively? Am J Surg 1995;169:245–53. [13] Ray EC, Nickels MW, Sayeed S, Sax HC. Predicting success after gastric bypass: the role of psychosocial and behavioral factors. Surgery 2003;134:555– 63.
485
[14] Jamal MK, DeMaria EJ, Johnson JM, et al. Insurance-mandated preoperative dietary counseling does not improve outcome and increased dropout rates in patients considering gastric bypass surgery for morbid obesity. Surg Obes Relat Dis 2006;2:122–7. [15] Ma Y, Pagoto SL, Olendzki BC, et al. Predictors of weight status following laparoscopic gastric bypass. Obes Surg 2006;16:1227–31. [16] Sugerman HJ. Bariatric surgery for severe obesity. J Assoc Acad Minor Phys 2001;12:129 –36. [17] Hildebrandt S. Effects of participation in bariatric support group after Roux-en-Y gastric bypass. Obes Surg 1998;8:535– 42. [18] Lutfi R, Torquati A, Sekhar N, Richards WO. Predictors of success after laparoscopic gastric bypass: a multivariate analysis of socioeconomic factors. Surg Endosc 2006;20:864 –7.