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Am I on Track? Evaluating Patient-Specific Weight Loss After Bariatric Surgery Using an Outcomes Calculator

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Individual weight loss outcomes after bariatric surgery can vary considerably. As a result, identifying and assisting patients who are not on track to reach their weight loss goals can be challenging.

Materials and Methods

Using a bariatric surgery outcomes calculator, which was formulated using a state-wide bariatric-specific data registry, predicted weight loss at 1 year after surgery was calculated on 658 patients who underwent bariatric surgery at 35 different bariatric surgery programs between 2015 and 2017. Patient characteristics, postoperative complications, and weight loss trajectories were compared between patients who met or exceeded their predicted weight loss calculation to those who did not based on observed to expected weight loss ratio (O:E) at 1 year after surgery.


Patients who did not meet their predicted weight loss at 1 year (n = 237, 36%) had a mean O:E of 0.71, while patients who met or exceeded their prediction (n = 421, 63%) had a mean O:E = 1.14. At 6 months, there was a significant difference in the percent of the total amount of predicted weight loss between the groups (88% of total predicted weight loss for those that met their 1-year prediction vs 66% for those who did not, p < 0.0001). Age, gender, procedure type, and risk-adjusted complication rates were similar between groups.


Using a bariatric outcomes calculator can help set appropriate weight-loss expectations after surgery and also identify patients who may benefit from additional therapy prior to reaching their weight loss nadir.

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  1. Azagury D, Mokhtari TE, Garcia L, et al. Heterogeneity of weight loss after gastric bypass, sleeve gastrectomy, and adjustable gastric banding. Surgery. 2019;165(3):565–70.

    Article  Google Scholar 

  2. Carlin AM, Zeni TM, English WJ, et al. The comparative effectiveness of sleeve gastrectomy, gastric bypass, and adjustable gastric banding procedures for the treatment of morbid obesity. Ann Surg. 2013;257(5):791–7.

    Article  Google Scholar 

  3. Still CD, Wood GC, Chu X, et al. Clinical factors associated with weight loss outcomes after Roux-en-Y gastric bypass surgery. Obesity (Silver Spring). 2014;22(3):888–94.

    Article  Google Scholar 

  4. Livhits M, Mercado C, Yermilov I, et al. Preoperative predictors of weight loss following bariatric surgery: systematic review. Obes Surg. 2012;22(1):70–89.

    Article  Google Scholar 

  5. Campos GM, Rabl C, Mulligan K, et al. Factors associated with weight loss after gastric bypass. Arch Surg. 2008;143(9):877–83. discussion 884

    Article  Google Scholar 

  6. Wood GC, Benotti P, Gerhard GS, et al. A patient-centered electronic tool for weight loss outcomes after Roux-en-Y gastric bypass. J Obes. 2014;2014:364941.

    Article  Google Scholar 

  7. Wood MH, Carlin AM, Ghaferi AA, et al. Association of race with bariatric surgery outcomes. JAMA Surg. 2019;154(5):e190029.

    Article  Google Scholar 

  8. Birkmeyer NJ, Share D, Campbell Jr DA, et al. Partnering with payers to improve surgical quality: the Michigan plan. Surgery. 2005;138(5):815–20.

    Article  Google Scholar 

  9. Gilhooly DA, Cole M, Moonesinghe SR. The evaluation of risk prediction models in predicting outcomes after bariatric surgery: a prospective observational cohort pilot study. Perioper Med (Lond). 2018;7:6.

    Article  Google Scholar 

  10. Wise ES, Hocking KM, Kavic SM. Prediction of excess weight loss after laparoscopic Roux-en-Y gastric bypass: data from an artificial neural network. Surg Endosc. 2016;30(2):480–8.

    Article  Google Scholar 

  11. Montero PN, Stefanidis D, Norton HJ, et al. Reported excess weight loss after bariatric surgery could vary significantly depending on calculation method: a plea for standardization. Surg Obes Relat Dis. 2011;7(4):531–4.

    Article  Google Scholar 

  12. van de Laar A, de Caluwe L, Dillemans B. Relative outcome measures for bariatric surgery. Evidence against excess weight loss and excess body mass index loss from a series of laparoscopic Roux-en-Y gastric bypass patients. Obes Surg. 2011;21(6):763–7.

    Article  Google Scholar 

  13. van de Laar AW, de Brauw M, Bruin SC, et al. Weight-independent percentile chart of 2880 gastric bypass patients: a new look at bariatric weight loss results. Obes Surg. 2016;26(12):2891–8.

    Article  Google Scholar 

  14. Ferriby M, Pratt K, Noria S, et al. A comparison of perceived and calculated weight status classification congruence between pre- and post-bariatric surgery patients. Surg Obes Relat Dis. 2017;13(8):1405–11.

    Article  Google Scholar 

  15. Manning S, Pucci A, Carter NC, et al. Early postoperative weight loss predicts maximal weight loss after sleeve gastrectomy and Roux-en-Y gastric bypass. Surg Endosc. 2015;29(6):1484–91.

    Article  Google Scholar 

  16. Mor A, Sharp L, Portenier D, et al. 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(5):556–60.

    Article  Google Scholar 

  17. Ritz P, Caiazzo R, Becouarn G, et al. Early prediction of failure to lose weight after obesity surgery. Surg Obes Relat Dis. 2013;9(1):118–21.

    Article  Google Scholar 

  18. Courcoulas AP, King WC, Belle SH, et al. Seven-year weight trajectories and health outcomes in the longitudinal assessment of bariatric surgery (LABS) study. JAMA Surg. 2018;153(5):427–34.

    Article  Google Scholar 

  19. Maciejewski ML, Arterburn DE, Van Scoyoc L, et al. Bariatric surgery and long-term durability of weight loss. JAMA Surg. 2016;151(11):1046–55.

    Article  Google Scholar 

  20. Schauer PR, Bhatt DL, Kirwan JP, et al. Bariatric surgery versus intensive medical therapy for diabetes—3-year outcomes. N Engl J Med. 2014;370(21):2002–13.

    Article  Google Scholar 

  21. Sjostrom L, Lindroos AK, Peltonen M, et al. Lifestyle, diabetes, and cardiovascular risk factors 10 years after bariatric surgery. N Engl J Med. 2004;351(26):2683–93.

    Article  Google Scholar 

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Blue Cross Blue Shield of Michigan/Blue Care Network. The funding source had no involvement in collection, analysis, and interpretation of data; writing of the report, or in the decision to submit the article for publication.

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Correspondence to Oliver A. Varban.

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Ethical Approval Statement

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.

Informed Consent Statement

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

Conflict of Interest

Oliver A. Varban reports other from Blue Cross Blue Shield of Michigan, during the conduct of the study. Aaron J. Bonham has nothing to disclose. Amanda L. Stricklen has nothing to disclose. Rachel Ross has nothing to disclose. Arthur M. Carlin reports other from Blue Cross Blue Shield of Michigan, during the conduct of the study. Jonathan F. Finks reports other from Blue Cross Blue Shield of Michigan, during the conduct of the study. Amir A. Ghaferi reports grants from AHRQ, grants from PCORI, and grants from Blue Cross Blue Shield of Michigan, outside the submitted work.

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Fig. 2
figure 2

Calibration curve demonstrating averages for each 5th percentile of weight loss

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Varban, O.A., Bonham, A.J., Stricklen, A.L. et al. Am I on Track? Evaluating Patient-Specific Weight Loss After Bariatric Surgery Using an Outcomes Calculator. OBES SURG 31, 3210–3217 (2021).

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