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 Table of Contents  
Year : 2022  |  Volume : 1  |  Issue : 1  |  Page : 30-33

Early weight loss: A determinant of total weight loss after bariatric surgery

Center for Metabolic Surgery, Wockhardt Hospitals, Mumbai, Maharashtra, India

Date of Submission04-Oct-2021
Date of Acceptance31-Dec-2021
Date of Web Publication09-Mar-2022

Correspondence Address:
Dr. Amrit Manik Nasta
Wockhardt Hospitals, Mumbai Central, Mumbai, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jbs.jbs_3_21

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Background: Bariatric surgery is the most effective weight loss intervention for patients with severe obesity. Several studies have shown wide variability in weight loss response between patients. The aim of the study is to identify comparative poor responders based on weight loss in the early postoperative period. Methods: A retrospective analysis of 125 patients who underwent primary bariatric surgery by a single surgeon and completed 1 year of follow-up was performed. Patients were divided into two groups based on % Total Weight loss (%TWL) at 1 month after surgery: Group 1-who lost <10% TWL and Group 2-who lost >10% TWL. The comparison of factors in both groups at different time points was executed using paired t-tests or analysis of variance. The relationships between Group 1 and Group 2 after 1 year follow-up period were assessed through linear regression analyses. Results: Seventy (56%) patients lost <10% TWL and 55 (44%) patients lost more than 10% TWL in 1 month after surgery. Mean weight loss at 1 month and 1 year after surgery was 9 ± 5.5 kg and 37 ± 13.3 kg in Group 1 compared to 16 ± 5.2 and 46 ± 16.4 kg in Group 2, respectively. Patients with >10%TWL at 1 month had significantly greater %TWL at 1 year (P = 0.001). Linear regression analysis showed a positive correlation between patients who lost >10%TWL 1 month after surgery and weight loss at 1 year. Conclusion: Postoperative percentage TWL of <10% at 1 month can be used as an early determinant of comparatively poor weight loss at 1 year. Early initiation of aggressive and multimodal treatment strategies is likely to improve overall weight loss outcomes after surgery.

Keywords: Bariatric, early, predictors, Roux-en-Y gastric bypass, sleeve gastrectomy, weight loss

How to cite this article:
Satheesh S, Shetty A, Nasta AM, Goel M, Goel R. Early weight loss: A determinant of total weight loss after bariatric surgery. J Bariatr Surg 2022;1:30-3

How to cite this URL:
Satheesh S, Shetty A, Nasta AM, Goel M, Goel R. Early weight loss: A determinant of total weight loss after bariatric surgery. J Bariatr Surg [serial online] 2022 [cited 2023 Sep 29];1:30-3. Available from: http://www.jbsonline.org/text.asp?2022/1/1/30/339262

  Introduction Top

Bariatric surgery is an established therapeutic option to achieve substantial weight loss along with improvement in comorbidities. Approximately 11% of patients fail to lose adequate weight following surgery.[1] Variation in weight loss is attributed to age, sex, genetic factors, procedure type, diet adherence, physical activity, and body fat distribution (gynecoid vs. android).[2],[3] Poor postoperative weight loss may also influence the metabolic effect of bariatric surgery, limiting the expected health benefits, including improvement in diabetes, hypertension, dyslipidemia, sleep apnea, and other comorbidities.[4],[5]

Few randomized controlled trials have reported statistically insignificant weight loss variance between commonly performed sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) surgeries.[6],[7] Established predictors of weight loss after bariatric surgery include age, preoperative weight loss, initial body mass index (BMI), depression score, eating behavior, and level of physical activity after surgery.[8],[9],[10],[11],[12],[13]

As weight usually stabilizes at 12–18 months after surgery, patients with comparatively less weight loss find it difficult to lose further. Early identification of these patients is likely to help delineate intervention strategies, including increased follow-up frequency, the addition of weight-loss medicines, etc. Through this study, we wish to determine early predictor(s) of nadir weight loss at 1 month itself after surgery.

  Methods Top

We performed a retrospective analysis of prospectively collected data of 125 patients who underwent bariatric surgery at our institution between January 1, 2013, and December 31, 2013. We included all consecutive patients who underwent primary bariatric surgery and completed 1 year of follow-up. Patients who underwent revision surgery were excluded from the study. A diagnosis of preoperative Type 2 diabetes mellitus (T2D), hypertension, and sleep apnea syndrome were based on the medical history and investigation reports.

Preoperative preparation

Before surgery, every patient underwent multidisciplinary evaluation by a bariatric surgeon, physician, anesthetist, counselor, and dietician. If required, the patients were also sent to an endocrinologist or psychiatrist for further evaluation. Patients with a history of alcohol intake or smoking were explained the enhanced risk related to healing, weight regain, and accelerated liver damage. They were refused surgery till they demonstrated adequate cessation. Every patient underwent upper gastrointestinal endoscopy to rule out significant upper gastrointestinal tract pathology. Polysomnography was performed for patients with symptoms of obstructive sleep apnea.

The patients were counseled in detail about the surgical options of SG and RYGB and related postoperative complications, nutritional deficiency, and redo surgery, if the need arises. In our center, patients with hiatus hernia or diabetes of more than 5 years duration were preferred for RYGB over SG. The patients with enlarged left liver lobe (over 15 cm on preoperative ultrasound) were put on low-calorie liquid diet for at least 2 weeks and admitted 1 day before the procedure. Deep-vein thrombosis prophylaxis was started 12 h before surgery with low-molecular-weight heparin subcutaneous injections and continued after surgery based on Caprini score. All surgeries were performed as per standard techniques.[14]

Weight charting was done on each follow-up visits, and patients were grouped based on total weight loss (TWL) percentage. The main outcome measure was postoperative TWL percentage (%TWL) and it was determined relative to weight on the day of surgery. %TWL was calculated as the difference of preoperative weight and postoperative weight divided by preoperative weight at baseline, with the quotient multiplied by 100.

%TWL = ([preoperative weight − weight at follow-up])/(preoperative weight) × 100.

The patients included in the study were divided into two groups based on %TWL 1 month after surgery. The first group included patients who lost <10%TWL and the second group included patients who lost more than 10%TWL at 1 month follow-up. Data were collected before surgery and postsurgically at 1 month, 3 months, 6 months, and 1 year.

Statistical analysis

All clinical data records were maintained on Microsoft Office Excel and analyzed statistically. Descriptive and summary statistics were calculated to gain a general perspective of the data. Continuous variables were expressed as mean and standard deviation, and categorical data were expressed as numbers or percentages. Student's t-test and Chi-square test were used to measure significant change between the various study groups. The comparisons between different time points were executed using paired t-tests or Wilcoxon signed-rank tests or analysis of variance. The relationships between early weight loss at 1 month and weight loss after 1-year follow-up period were assessed through linear regression analyses. P < 0.05 is considered to indicate significance in all tests. All statistical analyses were performed using SPSS software version 20.0 (IBM Corp., Armonk, NY, USA).

  Results Top

One hundred and twenty-five patients who underwent bariatric surgery at our center in the mentioned period were included in this analysis. Majority of the patients were female (61.1% females: 38.4% males) with a mean age of 40.8 years and a mean BMI of 44.9 kg/m2 before surgery. About 32% had preoperative T2D mellitus, and 46.4% had hypertension [Table 1]. SG and RYGB were performed in 108 (86.4%) and 17 (13.6%) patients, respectively. All procedures were successfully completed laparoscopically. No postoperative mortality, stenosis, and bleeding were identified at follow-up.
Table 1: Baseline demographics of patients enrolled in the study

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The postoperative mean %TWL at 1, 3, 6, and 12 months was 9.9% ± 4.63%, 17.6% ± 6.29%, 26.5% ± 6%, and 34.8% ± 8.54%, respectively.

70 (56%) patients lost <10% TWL at 1 month and were classified as Group 1, whereas Group 2 comprised 55 (44%) patients who lost more than 10%TWL 1 month after surgery. Patients had average weight loss of 9 kg and 37 kg in Group 1, while Group 2 lost 16 kg and 46 kg at 1 month and 1 year, respectively (P = 0.447) [Figure 1].
Figure 1: Comparison of mean weight loss (in kgs) between both the groups at 1 month and 1 year. TWL: Total weight loss

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Analysis of covariance, i.e., <10%TWL and >10%TWL with gender, age, BMI, prevalence of T2D, and hypertension were performed. Young and male patients were found to lose significantly more weight at 1 month [Table 2]. Other parameters such as BMI, surgery type, and preoperative T2D did not have any significant correlation with %TWL at 1 month.
Table 2: Factors associated with postoperative percentage total weight loss at 1 month in both groups

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Patients with >10%TWL at 1 month had significantly greater %TWL at 1 year (P = 0.001). Linear regression analysis showed a positive correlation between patients who lost >10%TWL 1 month after surgery and weight loss at 1 year. Multiple linear regression analyses were used to evaluate the relationship between %TWL at 1 year with %TWL at 1 month and other related co-factors [Table 3]. TWL more than or equal to 10% within the 1st month of surgery resulted in a significant weight loss (P = 0.01) after 1 year; coefficient being on the positive side as 4.114 with 95% confidence interval of 1–7.21. At 1 year, patients with BMI more than 40 kg/m2 lost more % TWL as compared to individuals with BMI <40 kg/m2 (Coefficient 4.12, P = 0.02). Furthermore, patients with hypertension lost less weight when compared to normotensive patients (coefficient 3.634, P = 0.034). Age, gender, surgical method, and preoperative diabetes mellitus were not found to be related to the %TWL at 1 year [Table 3].
Table 3: Analysis of the variables to see the predictors of weight loss at 1 year

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  Discussion Top

Bariatric surgery is an established technique to achieve significant weight loss in patients with morbid obesity.[15] However, studies have shown that the weight loss outcomes vary between patients and a proportion of patients lose comparatively less weight.[16]

In our study, patients who lost <10% and ≥10% weight at 1 month had statistical difference in %TWL at 1 year (P = 0.001). Manning et al. constructed weight loss charts for SG and showed a strong association between early postoperative weight loss and maximal weight loss achieved.[17] Obeidat and Shanti. demonstrated that patients who lost ≥15.7%EWL 1 month after surgery were more likely to achieve better weight loss outcomes after 2 years.[18] Silveira et al. reported that <5% weight loss at 1 month and <10% weight loss at 3 months is associated with suboptimal weight loss at 1 year.[19]

Andersen et al. reported that weight loss and predictors for long-term weight loss after SG are gender specific.[20] We did identify that younger patients and male gender had shown significant weight loss in the 1st month after the operation. This is similar to other studies suggesting that men lose significantly more weight than women at 6–12 months postsurgery.[21] However, in our study, weight loss at 1 year was not significantly different between genders.

Our study demonstrated %TWL at 1 month and preoperative BMI as independent predictors of %TWL at 1 year. These findings are aligned with results published by Grover et al. wherein patients with a preoperative BMI ≥40 kg/m2 experienced a significantly greater %TWL at 2 years postoperative compared to those with a preoperative BMI <40 kg/m2.[16]

Based on our study, we propose that patients can be identified during the initial postoperative period as poor responders or being at risk for comparatively poor long-term weight loss outcomes. Thereafter, these patients can be offered the opportunity for adjunctive interventions that can enhance their weight loss response and the factors affecting weight loss are also identified and modified accordingly.[17] Furthermore, rescue strategies can be implemented such as frequent and intensive follow-ups to assess eating behavior, exercise limitations, identification of psychological reasons and to induct necessary changes to improve overall outcomes.[22]

Our study limitations include retrospective nature of the study, small sample size, and the study design lacked intervention(s) in poor responders to identify suitable strategies to improve overall outcomes.

  Conclusion Top

The findings from our study can help identify patients at risk of comparatively less nadir weight loss after surgery. Percentage TWL of 10% at 1 month has been identified as a predictor of weight loss at 1 year in this study. Larger studies are required to validate our findings and intervention studies are required to identify the effectiveness of weight-loss medicines, increased follow-up frequency, dietary interventions, regular exercises, counseling sessions, and social support for at-risk patients starting as early as 1 month after the procedure to achieve better weight loss.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study, formal consent is not required.

Informed consent

Informed consent was obtained from all individual participants included in the study.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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Courcoulas AP, King WC, Belle SH, Berk P, Flum DR, Garcia L, et al. Seven-year weight trajectories and health outcomes in the longitudinal assessment of bariatric surgery (LABS) study. JAMA Surg 2018;153:427-34.  Back to cited text no. 2
van de Laar AW, Acherman YI. Weight loss percentile charts of large representative series: A benchmark defining sufficient weight loss challenging current criteria for success of bariatric surgery. Obes Surg 2014;24:727-34.  Back to cited text no. 3
van de Laar AW, de Brauw LM, Meesters EW. Relationships between type 2 diabetes remission after gastric bypass and different weight loss metrics: Arguments against excess weight loss in metabolic surgery. Surg Obes Relat Dis 2016;12:274-82.  Back to cited text no. 4
Brissman M, Beamish AJ, Olbers T, Marcus C. Prevalence of insufficient weight loss 5 years after Roux-en-Y gastric bypass: Metabolic consequences and prediction estimates: A prospective registry study. BMJ Open 2021;11:e046407.  Back to cited text no. 5
Salminen P, Helmiö M, Ovaska J, Juuti A, Leivonen M, Peromaa-Haavisto P, et al. Effect of laparoscopic sleeve gastrectomy vs. laparoscopic Roux-en-Y gastric bypass on weight loss at 5 years among patients with morbid obesity: The SLEEVEPASS Randomized Clinical Trial. JAMA 2018;319:241-54.  Back to cited text no. 6
Peterli R, Wölnerhanssen BK, Peters T, Vetter D, Kröll D, Borbély Y, et al. Effect of laparoscopic sleeve gastrectomy vs. laparoscopic Roux-en-Y gastric bypass on weight loss in patients with morbid obesity: The SM-BOSS Randomized Clinical Trial. JAMA 2018;319:255-65.  Back to cited text no. 7
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Goel R, Goel M, Nasta AM, Vyas S, Dharia S, Hamrapurkar S. Portion control eating – A determinant of bariatric outcomes. Obes Surg 2018;28:3738-43.  Back to cited text no. 10
Averbukh Y, Heshka S, El-Shoreya H, Flancbaum L, Geliebter A, Kamel S, et al. Depression score predicts weight loss following Roux-en-Y gastric bypass. Obes Surg 2003;13:833-6.  Back to cited text no. 11
Guajardo-Salinas GE, Hilmy A, Martinez-Ugarte ML. Predictors of weight loss and effectiveness of Roux-en-Y gastric bypass in the morbidly obese Hispano-American population. Obes Surg 2008;18:1369-75.  Back to cited text no. 12
Alger-Mayer S, Polimeni JM, Malone M. Preoperative weight loss as a predictor of long-term success following Roux-en-Y gastric bypass. Obes Surg 2008;18:772-5.  Back to cited text no. 13
Nasta AM, Goel R, Dharia S, Goel M, Hamrapurkar S. Weight loss and comorbidity resolution 3 years after bariatric surgery – An Indian perspective. Obes Surg 2018;28:2712-9.  Back to cited text no. 14
de Hollanda A, Ruiz T, Jiménez A, Flores L, Lacy A, Vidal J. Patterns of weight loss response following gastric bypass and sleeve gastrectomy. Obes Surg 2015;25:1177-83.  Back to cited text no. 15
Grover BT, Morell MC, Kothari SN, Borgert AJ, Kallies KJ, Baker MT. Defining weight loss after bariatric surgery: A call for standardization. Obes Surg 2019;29:3493-9.  Back to cited text no. 16
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.  Back to cited text no. 17
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.  Back to cited text no. 18
Silveira FC, Docherty NG, Sallet PC, Moraes M, Monclaro T, Arruda E Silva M, et al. Early post-operative weight change after Roux-en-Y gastric bypass predicts weight loss at 12-month follow-up. Obes Surg 2020;30:5020-5.  Back to cited text no. 19
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Tymitz K, Kerlakian G, Engel A, Bollmer C. Gender differences in early outcomes following hand-assisted laparoscopic Roux-en-Y gastric bypass surgery: Gender differences in bariatric surgery. Obes Surg 2007;17:1588-91.  Back to cited text no. 21
Wang L, Sang Q, Zheng X, Du D, Zhang N, Lian D. Early weight loss following laparoscopic sleeve gastrectomy is predictive of long-term weight loss in morbidly obese Chinese. Obes Surg 2021;31:820-8.  Back to cited text no. 22


  [Figure 1]

  [Table 1], [Table 2], [Table 3]


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