Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Global variations in preoperative practices concerning patients seeking primary bariatric and metabolic surgery (PACT Study): A survey of 634 bariatric healthcare professionals



Bariatric and Metabolic Surgery (BMS) is a popular weight loss intervention worldwide, yet few scientific studies have examined variations in preoperative practices globally. This study aimed to capture global variations in preoperative practices concerning patients planned for BMS.


A 41-item questionnaire-based survey was designed and the survey link was freely distributed on social and scientific media platforms, email groups and circulated through personal connections of authors. The survey included eight parts: basic information; criteria for BMS; preoperative nutritional screening; preoperative weight loss; preoperative diets for liver size reduction; preoperative glycemic control; other laboratory investigations and preparations; decision making, education, and consents. Descriptive statistics were used to analyse data and graphs were used for representation where applicable.


Six hundred thirty-four bariatric healthcare professionals from 76 countries/regions completed the survey. Of these, n = 310 (48.9%) were from public hospitals, n = 466 (73.5%) were surgeons, and the rest were multidisciplinary professionals. More than half of respondents reported using local society/association guidelines in their practice (n = 310, 61.6%). The great majority of respondents routinely recommend nutritional screening preoperatively (n = 385, 77.5%), mandatory preoperative diets for liver size reduction (n = 220, 53.1%), routine screening for T2DM (n = 371, 90.7%), and mandate a glycemic control target before BMS in patients with T2DM (n = 203, 55.6%). However, less than half (n = 183, 43.9%) recommend mandatory preoperative weight loss to all patients. Most respondents (n = 296, 77.1%) recommend psychological intervention before surgery for patients diagnosed with psychological conditions. Variations were also identified in laboratory investigations and optimisation; and in the aspects of decision making, education and consent.


This survey identified significant global variations in preoperative practices concerning patients seeking primary BMS. Our findings could facilitate future research for the determination of best practice in these areas of variations, and consensus-building to guide clinical practice while we wait for that evidence to emerge.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Liver reducing diet (n = 341).
Fig. 2: Liver reducing diet duration (n = 341).
Fig. 3: Routine screening for T2DM (n = 365).
Fig. 4: Core members of MDT (n = 374).

Data availability

The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.


  1. Angrisani L, Santonicola A, Iovino P, Ramos A, Shikora S, Kow L. Bariatric surgery survey 2018: similarities and disparities among the 5 IFSO chapters. Obes Surg. 2021;31:1937–48.

    Article  Google Scholar 

  2. Arterburn DE, Telem DA, Kushner RF, Courcoulas AP. Benefits and risks of bariatric surgery in adults: a review. Jama. 2020;324:879–87.

    Article  Google Scholar 

  3. Cummings DE, Rubino F. Metabolic surgery for the treatment of type 2 diabetes in obese individuals. Diabetologia. 2018;61:257–64.

    Article  Google Scholar 

  4. Hazlehurst JM, Logue J, Parretti HM, Abbott S, Brown A, Pournaras DJ, et al. Developing integrated clinical pathways for the management of clinically severe adult obesity: a critique of NHS England policy. Curr Obes Rep. 2020;9:530–43.

    Article  Google Scholar 

  5. Mahawar KK, Small PK. Medical weight management before bariatric surgery: is it an evidence-based intervention or a rationing tool? Clin Obes. 2016;6:359–60.

    Article  CAS  Google Scholar 

  6. Kelley K, Clark B, Brown V, Sitzia J. Good practice in the conduct and reporting of survey research. Int J Qual Health Care. 2003;15:261–6.

    Article  Google Scholar 

  7. NIH conference. Gastrointestinal surgery for severe obesity. Consensus development conference panel. Ann Intern Med. 1991;115:956–61.

    Article  Google Scholar 

  8. Yermilov I, McGory ML, Shekelle PW, Ko CY, Maggard MA. Appropriateness criteria for bariatric surgery: beyond the NIH guidelines. Obesity. 2009;17:1521–7.

    Article  Google Scholar 

  9. Bhasker AG, Prasad A, Raj PP, Wadhawan R, Khaitan M, Agarwal AJ, et al. OSSI (obesity and metabolic surgery society of India) guidelines for patient and procedure selection for bariatric and metabolic surgery. Obes Surg. 2020;30:2362–8.

    Article  CAS  Google Scholar 

  10. Yang W, Wang C. Chinese Obesity and Metabolic Surgery Collaborative. Metabolic Surgery Needs Stronger Endorsement in Asian T2DM Patients with Low BMI. Obes Surg. 2022;32:212–13.

    Article  Google Scholar 

  11. Kasama K, Mui W, Lee WJ, Lakdawala M, Naitoh T, Seki Y, et al. IFSO-APC consensus statements 2011. Obes Surg. 2012;22:677–84.

    Article  Google Scholar 

  12. Livingston EH. Pitfalls in using BMI as a selection criterion for bariatric surgery. Curr Opin Endocrinol Diabetes Obes. 2012;19:347–51.

    Article  Google Scholar 

  13. Oskrochi Y, Majeed A, Easton G. Biting off more than we can chew: is BMI the correct standard for bariatric surgery eligibility? Br J Gen Pract. 2015;65:482–3.

    Article  Google Scholar 

  14. Guan B, Yang J, Chen Y, Yang W, Wang C. Nutritional deficiencies in Chinese patients undergoing gastric bypass and sleeve gastrectomy: prevalence and predictors. Obes Surg. 2018;28:2727–36.

    Article  Google Scholar 

  15. Wang C, Guan B, Yang W, Yang J, Cao G, Lee S. Prevalence of electrolyte and nutritional deficiencies in Chinese bariatric surgery candidates. Surg Obes Relat Dis. 2016;12:629–34.

    Article  Google Scholar 

  16. Zhang W, Fan M, Wang C, Mahawar K, Parmar C, Chen W, et al. Global Bariatric Research Collaborative. Hair Loss After Metabolic and Bariatric Surgery: a Systematic Review and Meta-analysis. Obes Surg. 2021;31:2649–59.

    Article  Google Scholar 

  17. Zhang W, Fan M, Wang C, Mahawar K, Parmar C, Chen W, et al. Global Bariatric Research Collaborative. Importance of Maintaining Zinc and Copper Supplement Dosage Ratio After Metabolic and Bariatric Surgery. Obes Surg. 2021;31:3339–40.

    Article  Google Scholar 

  18. Elhag W, El Ansari W. Nutritional Deficiencies Among Adolescents Before and After Sleeve Gastrectomy: First Study with 9-Year Followup. Obes Surg. 2022;32:284–94.

    Article  Google Scholar 

  19. Bretault M, Zaharia R, Vigan M, Vychnevskaia K, Raffin-Sanson ML, Crenn P, et al. Complications requiring intensive nutritional care after bariatric surgery result in more long-term weight loss but has no impact on nutritional deficiencies and depression-anxiety scores. Obes Surg. 2021;31:4767–75.

    Article  Google Scholar 

  20. Gasmi A, Bjørklund G, Mujawdiya PK, Semenova Y, Peana M, Dosa A, et al. Micronutrients deficiences in patients after bariatric surgery. Eur J Nutr. 2022;61:55–67.

    Article  Google Scholar 

  21. Mahawar KK, Bhasker AG, Bindal V, Graham Y, Dudeja U, Lakdawala M, et al. Zinc deficiency after gastric bypass for morbid obesity: a systematic review. Obes Surg. 2017;27:522–9.

    Article  Google Scholar 

  22. Kumar P, Hamza N, Madhok B, De Alwis N, Sharma M, Miras AD, et al. Copper deficiency after gastric bypass for morbid obesity: a systematic review. Obes Surg. 2016;26:1335–42.

    Article  Google Scholar 

  23. O’Kane M, Parretti HM, Pinkney J, Welbourn R, Hughes CA, Mok J, et al. British obesity and metabolic surgery society guidelines on perioperative and postoperative biochemical monitoring and micronutrient replacement for patients undergoing bariatric surgery-2020 update. Obes Rev. 2020;21:e13087.

    PubMed  PubMed Central  Google Scholar 

  24. Mechanick JI, Apovian C, Brethauer S, Timothy Garvey W, Joffe AM, Kim J, et al. Clinical practice guidelines for the perioperative nutrition, metabolic, and nonsurgical support of patients undergoing bariatric procedures - 2019 update: cosponsored by American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic and Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists. Obesity. 2020;28:O1–o58.

    Article  Google Scholar 

  25. Sun Y, Liu B, Smith JK, Correia MLG, Jones DL, Zhu Z, et al. Association of preoperative body weight and weight loss with risk of death after bariatric surgery. JAMA Netw Open. 2020;3:e204803.

    Article  Google Scholar 

  26. Eng V, Garcia L, Khoury H, Morton J, Azagury D. Preoperative weight loss: is waiting longer before bariatric surgery more effective? Surg Obes Relat Dis. 2019;15:951–7.

    Article  Google Scholar 

  27. Schiavo L, Scalera G, Sergio R, De Sena G, Pilone V, Barbarisi A. Clinical impact of Mediterranean-enriched-protein diet on liver size, visceral fat, fat mass, and fat-free mass in patients undergoing sleeve gastrectomy. Surg Obes Relat Dis. 2015;11:1164–70.

    Article  Google Scholar 

  28. Holderbaum M, Casagrande DS, Sussenbach S, Buss C. Effects of very low calorie diets on liver size and weight loss in the preoperative period of bariatric surgery: a systematic review. Surg Obes Relat Dis. 2018;14:237–44.

    Article  Google Scholar 

  29. Samuel N, Mustafa A, Hawkins H, Wei N, Boyle M, De Alwis N, et al. Influence of Pre-operative HbA1c on Bariatric Surgery Outcomes-the Sunderland (UK) Experience. ObesSurg. 2022;32:42–47.

    Google Scholar 

  30. de Raaff CAL, Gorter-Stam MAW, de Vries N, Sinha AC, Jaap Bonjer H, Chung F, et al. Perioperative management of obstructive sleep apnea in bariatric surgery: a consensus guideline. Surg Obes Relat Dis. 2017;13:1095–109.

    Article  Google Scholar 

  31. de Raaff CAL, de Vries N, van Wagensveld BA. Obstructive sleep apnea and bariatric surgical guidelines: summary and update. Curr Opin Anaesthesiol. 2018;31:104–9.

    Article  Google Scholar 

  32. O’Reilly E, Doherty L, O’Boyle C. How relevant is pre-operative obstructive sleep apnoea in the asymptomatic bariatric surgery patient? Obes Surg. 2020;30:969–74.

    Article  Google Scholar 

  33. Wolvers PJD, Ayubi O, Bruin SC, Hutten BA, Brandjes DPM, Meesters EW, et al. Smoking behaviour and beliefs about smoking cessation after bariatric surgery. Obes Surg. 2021;31:239–49.

    Article  Google Scholar 

  34. David LA, Sijercic I, Cassin SE. Preoperative and post-operative psychosocial interventions for bariatric surgery patients: A systematic review. Obes Rev. 2020;21:e12926.

    Article  Google Scholar 

  35. Graham Y, Callejas-Diaz L, Parkin L, Mahawar K, Small PK, Hayes C. Exploring the patient-reported impact of the pharmacist on pre-bariatric surgical assessment. Obes Surg. 2019;29:891–902.

    Article  Google Scholar 

  36. Lee YC, Wu WL. Shared decision making and choice for bariatric surgery. Int J Environ Res Public Health. 2019;16:4966.

    Article  Google Scholar 

  37. Hamadi R, Marlow CF, Nassereddine S, Taher A, Finianos A. Bariatric venous thromboembolism prophylaxis: an update on the literature. Expert Rev Hematol. 2019;12:763–71.

    Article  CAS  Google Scholar 

  38. Ruiz-Tovar J, Llavero C. Thromboembolic prophylaxis for morbidly obese patients undergoing bariatric surgery. Adv Exp Med Biol. 2017;906:9–13.

    Article  CAS  Google Scholar 

  39. Imberti D, Baldini E, Pierfranceschi MG, Nicolini A, Cartelli C, De Paoli M, et al. Prophylaxis of venous thromboembolism with low molecular weight heparin in bariatric surgery: a prospective, randomised pilot study evaluating two doses of parnaparin (BAFLUX Study). Obes Surg. 2014;24:284–91.

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations



WY and KM conceived and designed the idea, wrote, and drafted the manuscript. WY, YG, and KM led the data analysis, interpretation, and manuscript preparation with input from all authors. All authors contributed to the survey design, survey distribution, data collection, editing, and revising the manuscript, and have read and approved the final manuscript.

Corresponding author

Correspondence to Wah Yang.

Ethics declarations

Competing interests

MOK has been paid honoraria by Novo Nordisk for services provided/consultancy and Johnson and Johnson for educational activities. AT reports grants from Novo Nordisk, personal fees from Novo Nordisk, non-financial support from Novo Nordisk, personal fees from Eli Lilly, non-financial support from Eli Lilly, personal fees from Janssen, personal fees from AZ, non-financial support from AZ, non-financial support from Impeto medical, non-financial support from Resmed, non-financial support from Aptiva, personal fees from BI, non-financial support from BI, personal fees from BMS, non-financial support from BMS, personal fees from NAPP, non-financial support from NAPP, personal fees from MSD, non-financial support from MSD, personal fees from Nestle, personal fees from Gilead, grants from Sanofi, and personal fees from Sanofi outside the submitted work. AAT is currently an employee of Novo Nordisk. This work was performed before AAT became a Novo Nordisk employee and Novo Nordisk had no role in this project. KM has been paid honoraria by Ethicon, Medtronic, Gore, Olympus, and various NHS trusts for educational activities and mentoring colleagues through One Anastomosis Gastric Bypass. The other authors declare that they have no conflicts of interest.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Yang, W., Abbott, S., Borg, CM. et al. Global variations in preoperative practices concerning patients seeking primary bariatric and metabolic surgery (PACT Study): A survey of 634 bariatric healthcare professionals. Int J Obes 46, 1341–1350 (2022).

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


Quick links