|Year : 2023 | Volume
| Issue : 1 | Page : 20-25
Early weight loss trajectory predicts outcome following bariatric surgery
Rosalind Walmsley1, Lynn Chong1, Priya Sumithran2, Michael Hii3
1 Department of Hepatobiliary and Upper Gastrointestinal Surgery, St Vincent's Hospital Melbourne, Australia
2 Department of Medicine, University of Melbourne, St Vincent's Hospital Melbourne, Australia
3 Department of Hepatobiliary and Upper Gastrointestinal Surgery, St Vincent's Hospital Melbourne; Department of Surgery, The University of Melbourne, St Vincent's Hospital Melbourne, Australia
|Date of Submission||08-Sep-2022|
|Date of Acceptance||04-Dec-2022|
|Date of Web Publication||25-Jan-2023|
172 Victoria Parade, East Melbourne, Victoria
Source of Support: None, Conflict of Interest: None
Background: Early identification of patients at risk of poor weight loss following bariatric surgery may provide an opportunity for timely addition of intervention to optimize weight loss. This study investigates the relationship between early postsurgery weight loss trajectory and final weight loss outcomes. Methods: Data from patients who underwent primary sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), or one-anastomosis gastric bypass (OAGB) between October 2014 and March 2020 at a single institution were analyzed retrospectively. Total weight loss percentage (%TWL) was calculated at 1, 3, 6, 9, 12, 18, 24, 30, and 36 months postsurgery. Regression analysis demonstrated associations between early weight loss and %TWL between 12 and 36 months. Multivariate analysis identified predictors of maximal weight loss (MWL) and insufficient weight loss (IWL). Results: Six hundred and sixteen patients met the inclusion criteria. Follow-up weights were available at 12 months for n = 571, 18 months for n = 382, 24 months for n = 344, 30 months for n = 198, and 36 months for n = 187. The median (interquartile range) MWL for SG, RYGB, and OAGB was 29.9% (24.3–35.7), 32.5% (27.5–38.2), and 38.0% (32.6–42.4), respectively. On multivariate linear regression, MWL was best predicted by 3–6-month %TWL after both SG (P < 0.001) and OAGB (P < 0.001) and by 6–9-month %TWL following RYGB (P < 0.001). Conclusion: Early weight loss predicts MWL and %TWL up to 36 months following laparoscopic SG, RYGB, and OAGB. Identification of poor weight loss responders early may represent an opportunity to intervene to optimize postsurgical outcomes.
Keywords: Bariatric surgery, early weight loss, obesity, one-anastomosis gastric bypass, roux-en-y gastric bypass, sleeve gastrectomy, weight outcomes
|How to cite this article:|
Walmsley R, Chong L, Sumithran P, Hii M. Early weight loss trajectory predicts outcome following bariatric surgery. J Bariatr Surg 2023;2:20-5
|How to cite this URL:|
Walmsley R, Chong L, Sumithran P, Hii M. Early weight loss trajectory predicts outcome following bariatric surgery. J Bariatr Surg [serial online] 2023 [cited 2023 Mar 22];2:20-5. Available from: http://www.jbsonline.org/text.asp?2023/2/1/20/368524
| Introduction|| |
The World Health Organization declared obesity a global epidemic in 1997, and prevalence rates continue to rise. Bariatric surgery is currently the most effective method to achieve sustained weight loss in the treatment of obesity; however, 20%–40% of patients experience insufficient weight loss (IWL), depending on the definition of “insufficient,” which is not currently standardized.
It is recognized that the majority of weight loss following bariatric surgery occurs in the initial 12–18 months postoperatively.,, There is also a correlation between the magnitude of weight loss following bariatric surgery and the resolution of obesity-related comorbidities, such as type 2 diabetes mellitus (T2DM) and hypertension (HTN).,,,,, Therefore, maximizing weight loss after bariatric surgery and prior to weight stabilization is clinically and metabolically important. Given that there are few consistent preoperative predictors of weight loss after bariatric surgery, the rate of early postoperative weight loss may provide the earliest indication of mid-to-long-term weight loss outcomes.,
If factors associated with a poor response to bariatric surgery can be identified early, additional therapies, such as adjuvant medication,, more intensive lifestyle modification,,,,, and allied health support, may be implemented to optimize long-term weight loss outcomes. This may also have a positive effect on obesity-related comorbidities.
The aim of this study was to investigate the association between early postoperative weight loss and percentage of total weight loss (%TWL) between 12- and 36-month follow-up, maximal weight loss (MWL), and overall IWL (<25% TWL at weight nadir) after bariatric surgery.
| Methods|| |
Study design and participants
This retrospective cohort study included consecutive patients aged over 18 years who underwent primary sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), or one-anastomosis gastric bypass (OAGB) at a single institution between October 31, 2014, and March 1, 2020, with at least 12-month follow-up.
Patients were eligible for surgery if they had a body mass index ≥ 40 kg/m2, or ≥ 35 kg/m2 with at least one obesity-related comorbidity, as consistent with the American Society for Metabolic and Bariatric Surgery clinical practice guidelines. Specific procedure selection was based on informed patient preference and surgeon recommendation following standard preoperative work-up, including routine endoscopy.
All procedures were performed by one of four experienced surgeons using a standardized laparoscopic technique. SG was performed using a 36Fr bougie with resection commencing 2 cm proximal to the pylorus. For RYGB, an 8-cm long gastric pouch was created over a 36Fr bougie with standard limb lengths of 60 cm alimentary and 90 cm biliopancreatic. The gastrojejunostomy was hand-sewn. For OAGB, the stomach was divided distal to the level of the angular incisure and then tubularized over a 36Fr bougie. A hand-sewn gastrojejunostomy was created with 180 cm of the small bowel bypassed.
Data were extracted from a prospectively maintained secure electronic data capture tool (REDCap)., Data relating to obesity-related complications, anthropometry, and patient demographics was collated.
Body weight (in kilograms, to one decimal place) was measured on the day of surgery, and at 1, 3, 6, 9, 12, 18, 24, 30, and 36 months postoperatively, up to the most recent time point available for each patient. A weight was allocated to the nearest time point as described above based on the date of the appointment attended. Percentage total weight loss (%TWL) was calculated at each time point. The weights documented were a mixture of self-reported and clinician-measured.
Recorded comorbidities included T2DM, HTN, obstructive sleep apnea, osteoarthritis (OA), ischemic heart disease, and gastroesophageal reflux disease (GORD) as recorded in medical records.
The primary outcome measure was percentage total weight loss (%TWL) at weight nadir (MWL). The secondary outcomes were %TWL from 12- to 36-month follow-up and IWL (defined as MWL <25% TWL at weight nadir).
Demographic and baseline anthropometric variables were compared between surgical procedures using Chi-squared, Fisher's exact, and Kruskal–Wallis tests. Categorical variables are reported as frequency and percentage. Continuous variables are expressed as median and interquartile range (IQR). Bonferroni post hoc analysis was used to assess differences between each surgical procedure. Multivariate linear and logistic regression was used to identify early weight loss periods and baseline characteristics associated with weight loss outcomes for each surgical procedure. Early weight loss was grouped according to 0–1, 1–3, 3–6, or 6–9 months postsurgery. Statistical significance was set at P < 0.05. All statistical analyses were performed with STATA software, version 15.1 (StataCorp, TX, USA).
| Results|| |
Demographics and descriptive analysis
Seven hundred and fifty-eight patients underwent primary bariatric surgery during the study period. One hundred and forty-two (18.7%) patients did not have follow-up data for the stipulated minimum 12-month period required for inclusion, leaving 616 patients for analysis (402 SG, 170 RYGB, and 44 OAGB). Of these patients, 571 (367 [91%] – SG, 161 [97%] – RYGB, and 43 [98%] – OAGB) had weight loss values available at 12-month follow-up, 382 (252 [63%] – SG, 97 [57%] – RYGB, and 33 [75%] – OAGB) at 18-month follow-up, 382 (220 [55%] – SG, 96 [56%] – RYGB, and 28 [64%] – OAGB) at 24-month follow-up, 198 (119 [30%] – SG, 57 [34%] – RYGB, and 22 [50%] – OAGB) at 30-month follow-up, and 187 (129 [32%] – SG, 40 [24%] – RYGB, and 18 [41%] – OAGB) at 36-month follow-up.
Preoperative demographic, anthropometric, and comorbidity data are presented in [Table 1]. Patients undergoing RYGB were on average 4 years older, and more likely to be diagnosed with several obesity-related comorbidities such as OA, HTN, and GORD than patients undergoing either SG or OAGB. Patients undergoing OAGB were on average heavier at baseline than patients undergoing either SG (+23 kg, P < 0.001) or RYGB (+18 kg, P < 0.001). No other demographic and comorbidity differences between groups were statistically significant.
Description of weight loss trends
[Figure 1] [Supplementary Table 1] shows the postoperative %TWL trend during follow-up for each surgical procedure.
|Figure 1: Postoperative percentage total weight loss (%TWL) trend up to 36-month|
Click here to view
The median (IQR) MWL for SG, RYGB, and OAGB was 29.9% (24.3–35.7), 32.5% (27.5–38.2), and 38.0% (32.6–42.4), respectively. On average, OAGB patients experienced an additional 7.1% (P < 0.001) and 3.5% (P = 0.030) MWL compared to SG and RYGB patients, respectively. RYGB patients lost an average of 3.5% (P < 0.001) more than their SG patient counterparts.
MWL most frequently occurred at the 12-month follow-up visit for SG (39.1%), RYGB (35.3%), and OAGB (34.1%) patients.
Association of early postoperative weight loss with maximal weight loss
%TWL at 0–1, 1–3, 3–6, and 6–9 months was all positively associated with MWL, with the exception of 0–1-month %TWL after OAGB. 3–6-month %TWL was the strongest predictor of MWL following both SG and OAGB. 6–9-month %TWL was the strongest predictor of MWL in RYGB patients.
Association of early postoperative weight loss with %TWL at 12–36 months
%TWL at 0–1, 1–3, 3–6, and 6–9 months was analyzed using linear regression for correlation with %TWL at each follow-up time point between 12 and 36 months postsurgery. The relative contribution of each early weight loss period to each model is demonstrated in [Table 2]. Early postoperative weight loss up to 9 months was positively associated with %TWL at 12–36 months following all three procedures (P < 0.05). 3–6-month %TWL was the strongest predictor of weight loss at all follow-up time points after OAGB. Both 3–6 month and 6–9 month %TWL were each the strongest predictor of weight loss at different time points after SG and RYGB.
|Table 2: Multivariate regression for early weight loss as predictor of 12-36 months and maximal weight loss#|
Click here to view
Effect of baseline demographics on the association of early postoperative weight loss with 12–36 months and maximal weight loss
Using univariate linear regression, baseline patient characteristics were analyzed for correlation with %TWL for each surgical procedure [Supplementary Table 2]. Factors initially significant on univariate analysis were then added to each multivariate model alongside the respective strongest early weight loss time period. Early weight loss remained the strongest predictor of weight loss at each follow-up time point and for MWL in every model, with exception to 24–36-month %TWL after OAGB and 36-month %TWL after RYGB, where no variable was significant on multivariate regression (P > 0.05).
Early postoperative prediction of insufficient weight loss
The early weight loss periods with the greatest influence on MWL were also tested for association with IWL (<25%TWL). One hundred and forty-three patients (113 [28.1%] – SG, 25 [14.7%] – RYGB, and 5 [11.4%] – OAGB) or 23.2% of the cohort met this criterion. Bonferroni post hoc analysis demonstrated that SG patients were more likely to experience IWL than both RYGB (P = 0.001) and OAGB (P = 0.036) patients.
On multivariate logistic regression analysis, IWL after SG was significantly predicted by early weight loss, with higher %TWL 3–6 months postsurgery reducing the likelihood of IWL (odds ratio [OR]: 0.70, 95% confidence interval [CI]: 0.63–0.78, P < 0.001). Increasing age (OR: 1.03, 95% CI: 1.01–1.06, P = 0.007) and male sex (OR: 2.37, 95% CI: 1.18–4.76, P = 0.015) also increased the likelihood of IWL post-SG. Higher 6–9 month %TWL reduced the likelihood of IWL after RYGB (OR: 0.70, 95% CI: 0.57–0.87, P = 0.001). This was the only statistically significant variable on multivariate analysis. The sample of OAGB patients with IWL was too small for multivariate analysis.
| Discussion|| |
Early identification of patients who are likely to have poor weight loss outcomes following bariatric surgery provides an opportunity for timely intervention to optimize weight loss. This retrospective, single-center analysis of 616 patients who underwent primary SG, RYGB, or OAGB aimed to examine the association between early weight loss and longer-term weight outcomes. Our main finding was that early weight loss after all procedures was a strong predictor of MWL, %TWL between 12 and 36 months, and overall risk of IWL.
The early time period that demonstrated the most influence on weight loss at 12–36 months varied according to surgery type. Multivariate analyses that included baseline demographic and comorbidity factors demonstrated that early weight loss was the strongest predictor of mid-term weight loss outcomes.
Previous research has reported similar findings. Manning et al. demonstrated that 3–6-month weight loss was the strongest positive predictor of MWL (%TWL) for both SG and RYGB. Philouze et al. also demonstrated a significant positive association between %TWL at 3 months postsurgery and %TWL at 24 months after SG. The correlation has been found as early as 1 month post-SG and RYGB and in final weight loss outcomes up to 36 months using both %TWL and percentage excess weight loss (%EWL).,,,,,,,,,,, While the specific predictive time periods vary between published reports, there is agreement that early weight loss patterns can be used to predict mid-to-long-term weight loss outcomes. Further research with longer follow-up periods of 5 to 10 years and beyond is warranted to determine whether this association persists to positively effect maintenance of weight loss.
While previous studies have demonstrated the effect of early weight loss on one or two mid-long-term time points, our study extends these findings by using weight records at 6-month intervals to show that the relationship exists as a continuous trend over time, up to and including 36-month follow-up.,,,,,,, We have also analyzed MWL as a separate outcome as it is often the outcome of the greatest clinical interest postoperatively and can occur at any point in time. Manning et al. is the only other study to also investigate MWL. We also compared four separate early weight loss periods ranging from 1 to 9 months postsurgery in order to select the time period with the strongest effect on long-term outcomes. Most similar studies compared two or three selected time points between 1 and 6 months and none included periods beyond 6 months in their models.,,,,,,, Given that in the present study, 6–9-month postoperative weight loss was often the strongest predictor of mid-term weight loss after both SG and RYGB, the inclusion of this period in future analyses and its acknowledgment as a potential key period in clinical practice may improve patient weight loss outcomes. Finally, to our knowledge, no other studies have assessed the utility of early weight loss to predict mid- or long-term weight loss outcomes after OAGB. Further research using larger sample sizes is warranted as rates of OAGB increase.
In our patient cohort, those undergoing SG were more likely to experience IWL than patients undergoing RYGB or OAGB. A 2019 systematic review by Barros et al. comparing weight loss between SG and RYGB concluded that after 5 years of follow-up, there is a tendency for greater excess weight loss achieved with RYGB; however, the difference was only statistically significant in four out of seven studies. To our knowledge, no other study has compared the likelihood of IWL between surgery types. Regardless, patients at risk of poor weight loss outcomes after either SG or RYGB can be identified early in their postoperative course, and therefore be considered for intervention to improve their postoperative course.
Several limitations affected the analysis and results of this study. First, there was a high rate of patients lost to follow-up by 12 months postsurgery, which potentially limits the statistical power of multivariate analyses. In this series, this most affected the OAGB group. Second, some weight loss measurements were obtained via patient self-reporting during phone interview follow-up appointments. This implicitly subjects the data to reporting bias. Finally, data were not collected on rates of improvement or resolution of obesity-related comorbidities, which is another important measure of bariatric surgery success and should be considered when assessing an individual patient's overall postoperative outcome.
Several observational studies have demonstrated an increase in postsurgical weight loss resulting from the addition of adjuvant therapies (such as obesity pharmacotherapy, and more intensive lifestyle interventions,,,,) implemented following weight loss plateau. It would be valuable for future research to prospectively study the impact that early intervention with these therapies has on mitigating the risk of IWL, as well as assessing the optimal timing and duration of such therapies.
| Conclusion|| |
As the key treatment for obesity, optimizing the efficacy of bariatric surgery for weight loss is important given the increasing incidence of this condition worldwide. Early weight loss was the strongest positive predictor of MWL and %TWL from 12 to 36 months following laparoscopic SG, RYGB, and OAGB. Patients at risk of IWL after bariatric surgery can also be identified by the rate of their early weight loss. This finding could potentially be utilized in clinical practice to identify poor responders early in the postoperative course to select for adjuvant interventions.
The establishment and maintenance of the prospective database for the use of future research was approved by the local ethics committee. All procedures performed were conducted in accordance with the institution and National Statement on Ethical Conduct in Human Research from the National Health and Medical Research Council. Informed consent was obtained from all individual participants prior to inclusion in the database. For this type of study, formal consent is not required.
Financial support and sponsorship
Priya Sumithran is supported by an Investigator Grant from the National Health and Medical Research Council.
Conflicts of interest
There are no conflicts of interest.
| References|| |
Colquitt JL, Pickett K, Loveman E, Frampton GK. Surgery for weight loss in adults. Cochrane Database Syst Rev 2014;2014:CD003641.
El Ansari W, Elhag W. Weight regain and insufficient weight loss after bariatric surgery: Definitions, prevalence, mechanisms, predictors, prevention and management strategies, and knowledge gaps-a scoping review. Obes Surg 2021;31:1755-66.
Marek RJ, Tarescavage AM, Ben-Porath YS, Ashton K, Merrell Rish J, Heinberg LJ. Using presurgical psychological testing to predict 1-year appointment adherence and weight loss in bariatric surgery patients: Predictive validity and methodological considerations. Surg Obes Relat Dis 2015;11:1171-81.
Barhouch AS, Padoin AV, Casagrande DS, Chatkin R, Süssenbach SP, Pufal MA, et al.
Predictors of excess weight loss in obese patients after gastric bypass: A 60-month follow-up. Obes Surg 2016;26:1178-85.
Kindel T, Lomelin D, McBride C, Kothari V, Thompson J. The time to weight-loss steady state after gastric bypass predicts weight-loss success. Obes Surg 2016;26:327-31.
Obeidat F, Shanti H. Early weight loss as a predictor of 2-year weight loss and resolution of comorbidities after sleeve gastrectomy. Obes Surg 2016;26:1173-7.
Sjöholm K, Sjöström E, Carlsson LM, Peltonen M. Weight change-adjusted effects of gastric bypass surgery on glucose metabolism: 2 and 10-year results from the Swedish Obese Subjects (SOS) study. Diabetes Care 2016;39:625-31.
Brethauer SA, Aminian A, Romero-Talamás H, Batayyah E, Mackey J, Kennedy L, et al.
Can diabetes be surgically cured? Long-term metabolic effects of bariatric surgery in obese patients with type 2 diabetes mellitus. Ann Surg 2013;258:628-36.
Sugerman HJ, Wolfe LG, Sica DA, Clore JN. Diabetes and hypertension in severe obesity and effects of gastric bypass-induced weight loss. Ann Surg 2003;237:751-6.
Stenberg E, Rask E, Szabo E, Näslund I, Ottosson J. The effect of laparoscopic gastric bypass surgery on insulin resistance and glycosylated hemoglobin A1c: A 2-year follow-up study. Obes Surg 2020;30:3489-95.
Ching SS, Cheng AK, Kong LW, Lomanto D, So JB, Shabbir A. Early outcomes of laparoscopic sleeve gastrectomy in a multiethnic Asian cohort. Surg Obes Relat Dis 2016;12:330-7.
Hindle A, de la Piedad Garcia X, Brennan L. Early post-operative psychosocial and weight predictors of later outcome in bariatric surgery: A systematic literature review. Obes Rev 2017;18:317-34.
Cottam S, Cottam D, Cottam A. Sleeve gastrectomy weight loss and the preoperative and postoperative predictors: A systematic review. Obes Surg 2019;29:1388-96.
Stanford FC, Alfaris N, Gomez G, Ricks ET, Shukla AP, Corey KE, et al.
The utility of weight loss medications after bariatric surgery for weight regain or inadequate weight loss: A multi-center study. Surg Obes Relat Dis 2017;13:491-500.
Nor Hanipah Z, Nasr EC, Bucak E, Schauer PR, Aminian A, Brethauer SA, et al.
Efficacy of adjuvant weight loss medication after bariatric surgery. Surg Obes Relat Dis 2018;14:93-8.
Egberts K, Brown WA, Brennan L, O'Brien PE. Does exercise improve weight loss after bariatric surgery? A systematic review. Obes Surg 2012;22:335-41.
Sheets CS, Peat CM, Berg KC, White EK, Bocchieri-Ricciardi L, Chen EY, et al.
Post-operative psychosocial predictors of outcome in bariatric surgery. Obes Surg 2015;25:330-45.
Søndergaard Nielsen M, Rasmussen S, Just Christensen B, Ritz C, le Roux CW, Berg Schmidt J, et al.
Bariatric surgery does not affect food preferences, but individual changes in food preferences may predict weight loss. Obesity (Silver Spring) 2018;26:1879-87.
Mundi MS, Lorentz PA, Swain J, Grothe K, Collazo-Clavell M. Moderate physical activity as predictor of weight loss after bariatric surgery. Obes Surg 2013;23:1645-9.
Orth WS, Madan AK, Taddeucci RJ, Coday M, Tichansky DS. Support group meeting attendance is associated with better weight loss. Obes Surg 2008;18:391-4.
Mechanick JI, Youdim A, Jones DB, Garvey WT, Hurley DL, McMahon MM, et al.
Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient – 2013 update: Cosponsored by American association of clinical endocrinologists, the obesity society, and American society for metabolic & bariatric surgery. Obesity (Silver Spring) 2013;21 Suppl 1:S1-27.
Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. Research electronic data capture (REDCap) – A metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform 2009;42:377-81.
Harris PA, Taylor R, Minor BL, Elliott V, Fernandez M, O'Neal L, et al.
The REDCap consortium: Building an international community of software platform partners. J Biomed Inform 2019;95:103208.
Manning S, Pucci A, Carter NC, Elkalaawy M, Querci G, Magno S, et al.
Early postoperative weight loss predicts maximal weight loss after sleeve gastrectomy and Roux-en-Y gastric bypass. Surg Endosc 2015;29:1484-91.
Philouze G, Voitellier E, Lacaze L, Huet E, Gancel A, Prévost G, et al.
Excess body mass index loss at 3 months: A predictive factor of long-term result after sleeve gastrectomy. J Obes 2017;2017:2107157.
Chew CAZ, Tan IJ, Ng HJ, Lomanto D, So J, Shabbir A. Early weight loss after laparoscopic sleeve gastrectomy predicts midterm weight loss in morbidly obese Asians. Surg Obes Relat Dis 2017;13:1966-72.
McNickle AG, Bonomo SR. Predictability of first-year weight loss in laparoscopic sleeve gastrectomy. Surg Endosc 2017;31:4145-9.
Steinbeisser M, McCracken J, Kharbutli B. Laparoscopic sleeve gastrectomy: Preoperative weight loss and other factors as predictors of postoperative success. Obes Surg 2017;27:1508-13.
Ritz P, Caiazzo R, Becouarn G, Arnalsteen L, Andrieu S, Topart P, et al.
Early prediction of failure to lose weight after obesity surgery. Surg Obes Relat Dis 2013;9:118-21.
Mor A, Sharp L, Portenier D, Sudan R, Torquati A. Weight loss at first postoperative visit predicts long-term outcome of roux-en-Y gastric bypass using duke weight loss surgery chart. Surg Obes Relat Dis 2012;8:556-60.
Nikolić M, Kruljac I, Kirigin L, Mirošević G, Ljubičić N, Nikolić BP, et al.
Initial weight loss after restrictive bariatric procedures may predict mid-term weight maintenance: Results from a 12-month pilot trial. Bariatr Surg Pract Patient Care 2015;10:68-73.
Cottam A, Billing J, Cottam D, Billing P, Cottam S, Zaveri H, et al.
Long-term success and failure with SG is predictable by 3 months: A multivariate model using simple office markers. Surg Obes Relat Dis 2017;13:1266-70.
Barros F, Negrão MG, Negrão GG. Weight loss comparison after sleeve and roux-en-Y gastric bypass: Systematic review. Arq Bras Cir Dig 2019;32:e1474.
[Table 1], [Table 2]