Back To Search Results

Bariatric Surgery Preoperative Assessment

Editor: Mark W. Jones Updated: 7/8/2023 11:07:39 PM


Obesity is an ever-growing concern throughout the world. In the last 3 decades, obesity has risen by 27.5% for adults and 47.1% for children internationally.[1] In the United States, the National Health and Nutrition Examination Survey (NHANES) recorded the prevalence of obesity from 2015 to 2016 at 18.5% in adolescents and 39.6% in adults.[2] 

Individuals with obesity have a higher prevalence of chronic health conditions such as hypertension, osteoarthritis, diabetes, and cardiovascular disease, as well as increased surgical complications and overall mortality.[3][4] Dietary modification and increased physical activity are the initial management strategies for obesity.

Guidelines for nonoperative obesity management are designed to assist patients in achieving clinically significant weight loss, defined as weight loss ≥5% of initial body weight.[5] Multiple diets have demonstrated potential for weight loss, and choosing a diet with the best chance of patient compliance is recommended. To achieve and sustain significant results, the guidelines encourage 14 counseling sessions targeting the behavioral aspects of obesity in the first 6 months of attempted weight loss with regular follow-up appointments after that.[6] Increasing physical activity also promotes weight loss. However, guidelines and a better understanding of the physiology and psychology of obesity are sometimes not enough.

Weight loss surgery has recently become another option to assist patients with significant and sustainable weight loss. With surgical advances and an improved understanding of the mechanisms of weight loss surgery, surgical management of severe obesity and metabolic disorders provides significant benefits for individuals struggling with obesity.[7] 

An essential step in weight loss surgery is the preoperative assessment. The preoperative assessment takes an in-depth, multidisciplinary approach to identify patients who qualify for weight loss surgery and would likely benefit from one of the recognized procedures. Weight loss surgery is not to be undertaken lightly. There are preoperative barriers to negotiate and postoperative guidelines to follow. Patients undergoing weight loss surgery require extensive education in the preoperative period to facilitate an understanding of the procedure and improve postoperative outcomes.


Register For Free And Read The Full Article
Get the answers you need instantly with the StatPearls Clinical Decision Support tool. StatPearls spent the last decade developing the largest and most updated Point-of Care resource ever developed. Earn CME/CE by searching and reading articles.
  • Dropdown arrow Search engine and full access to all medical articles
  • Dropdown arrow 10 free questions in your specialty
  • Dropdown arrow Free CME/CE Activities
  • Dropdown arrow Free daily question in your email
  • Dropdown arrow Save favorite articles to your dashboard
  • Dropdown arrow Emails offering discounts

Learn more about a Subscription to StatPearls Point-of-Care


Body mass index (BMI) is a widely used screening tool to assess weight status. Obesity in adults is typically defined as a BMI ≥30. It is further categorized into different classes based on increasing intervals of BMI: class 1 obesity ranges from 30 to 34.9, class 2 obesity ranges from 35 to 39.9, and class 3 obesity, or severe or severe obesity, is defined as a BMI ≥40.[8] Obesity in children is defined as a sex-specific BMI ≥95th percentile and severe obesity >120th percentile.[2] 

Obesity is a multifactorial disease process; genetics and environment play a role in the development of obesity.[9][8] Medications, diet, thyroid function, mood disorders, lifestyle, genetics, and socioeconomic status or ethnicity can influence obesity.[8] Weight gain results from an excess of consumed calories compared to energy expended. For some individuals, creating a negative energy balance is sufficient for weight loss and maintaining a healthy BMI. Other individuals have minimal results with decreasing calories consumed and increasing physical activity.

The body invokes compensatory measures when placed in a negative expenditure state, either by increasing the drive for food or altering the utilization of resources.[10] Weight loss surgery can be considered a viable therapeutic option when dietary and lifestyle modifications alone are insufficient to manage obesity or in cases where patients have metabolic disorders.[8]  

Weight loss procedures have traditionally been classified as either malabsorptive or restrictive procedures. However, this mindset is evolving along with the understanding of the physiologic mechanisms of weight loss and how weight loss procedures influence these mechanisms.[11] According to a global survey conducted in 2014, sleeve gastrectomy emerged as the most frequently performed weight loss surgery procedure, followed by the Roux-en-Y gastric bypass and the adjustable gastric band.[12] In 2018, over 250,000 weight loss procedures were recorded in the United States.[13] 

All surgical interventions for obesity or metabolic conditions require an in-depth preoperative assessment. The goals of the assessment are to identify appropriate candidacy for the procedure; identify, assess, and offer interventions for comorbidities that increase intraoperative morbidity and mortality; obtain informed consent; and ensure the patient understands the procedure and its risks. A thorough preoperative assessment improves outcomes in patients undergoing weight loss surgery.[14]

Issues of Concern

Patients may qualify for weight loss surgery if they have failed nonsurgical weight management and present with a BMI >40. Patients may also qualify if nonsurgical management has failed and the BMI is >35 in the presence of an obesity-related comorbidity such as type 2 diabetes, hypertension, osteoarthritis, coronary artery disease, or major depression.[14] Weight loss surgery may also be indicated for patients with a BMI <35 in the setting of significant metabolic dysfunction, such as diabetes that remains uncontrolled despite optimal medical therapy.[15][16]

Patient Age

Consideration of the age of the patient is essential. Weight loss surgery in patients under 18 years of age is controversial. However, the risk of developing obesity-related comorbidity increases the longer an individual is obese; children with obesity are therefore at increased risk of obesity-related complications.[17] 

Older guidelines recommended postponing weight loss surgery in adolescence, ages 10 through 19, until prospective patients have achieved a Tanner stage 4 maturity level or 95% of linear growth determined by bone age.[18] The American Society for Metabolic and Bariatric Surgery Pediatric Committee recommends focusing on comorbidity severity and early weight loss surgery to decrease and possibly reverse the effects of obesity-related comorbidities.[19] 

The Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS), a prospective, multi-institutional study, indicates that metabolic surgery is safe, effective, and does not impact future growth or development.[18] This study's overall complication rate for weight loss surgery in adolescents was approximately 14%.[20] Data collected from the National Surgical Quality Improvement Data reveal that the most common early complications of weight loss surgery in adolescents are urinary tract infections and surgical sites. Long-term complications in adolescents undergoing weight loss surgery include gastroesophageal reflux disease, incisional hernia, treatment failure requiring a second procedure, and nutritional deficiencies.[20] When considering weight loss surgery in adolescents with obesity, the ability to consent, the family environment, patient compliance with therapy, the risk of complications, and overall future health must be considered. 

Adults over 60 years of age also warrant careful preoperative assessment. Although obesity profoundly affects life expectancy and overall quality of life, older adults are more likely to have multiple comorbidities or disabilities that increase the risk of adverse events of weight loss surgery and negatively impact postoperative recovery. These complications and adverse events may worsen the quality of life rather than improve it.[21] Older adults considering weight loss surgery must be extensively counseled regarding its risks and benefits within the context of reasonable life expectancy. To facilitate these discussions, functional status can be measured and used as a predictive tool for postoperative morbidity and mortality; a lower baseline functional status indicates increased postoperative complications.[22][23][24] However, overall life expectancy continues to increase, and obesity is present in the older population; age should not be used as an absolute contraindication to weight loss surgery.  

Contraindications to Weight Loss Surgery

Contraindications for weight loss surgery include the risk of intraoperative complications and the dangers of poor patient compliance with therapeutic regimens in the postoperative period. The American Society of Anesthesiologists (ASA) physical status classification system evaluates perioperative comorbidities to assess operative risk, stratifying patients into 6 classes. Patients meeting Classes IV or V criteria have a high risk of intraoperative mortality; weight loss surgery would not be recommended.[25] 

Patients who cannot understand the operation or its future implications are not candidates for weight loss surgery. Patients with poorly controlled mental illness, eating disorders, alcohol use disorder, or any disease process that impairs their ability to understand the importance of lifestyle modification as an adjunct to weight loss surgery will likely benefit from a referral for formal psychological evaluation and treatment in the preoperative period.[26] The benefits of such a referral and treatment are particularly well documented in patients with eating disorders.[27]  All patients considering weight loss surgery must be screened for alcohol use disorder (AUD) and substance use during the preoperative assessment. The Longitudinal Assessment of Bariatric Surgery-2 (LABS-2) prospective observational study evaluated AUD and illicit substance use after weight loss surgery and found that one-fifth of participants reported AUD symptoms and increased substance use.[28] 

Finally, a lack of postoperative support can preclude a patient from weight loss surgery. Many patients require postoperative care in a rehabilitative facility, some of which cannot accept patients over a certain weight. Additionally, social support is needed to follow guidelines, attend postoperative visits, and maintain a healthy lifestyle following the procedure.[27]

Preoperative Assessment

Patients that meet the criteria for weight loss surgery must undergo an extensive preoperative assessment process. This process is best undertaken with a multidisciplinary team of experts, including the bariatric surgeon, a registered dietitian, a behavioral medicine professional, nurse educators, and possibly subspecialty providers such as cardiologists, pulmonologists, endocrinologists, and anesthesiologists. This preoperative assessment process evaluates and manages all aspects of the procedure and requires multiple appointments, educational sessions, planning, additional laboratory and diagnostic testing, and medical interventions as dictated by the clinical situation.[16]

A comprehensive medical history must be obtained, and a thorough physical examination must be performed. The patient must undergo a complete metabolic assessment to identify and assess comorbidities.[29] The failure of an implemented medically supervised diet plan must be documented.[16] A comprehensive understanding of the patient and their history facilitates the identification of factors impacting their obesity and allows for the planning necessary to ensure postoperative weight loss.

Metabolic assessment includes a complete blood count, complete metabolic panel, fasting blood glucose, hemoglobin A1c, lipid panel, urinalysis, and coagulation studies. The patient's overall nutritional status must be objectively evaluated with serum vitamin B12, folic acid, vitamin D, and iron studies. Serum albumin and prealbumin are important indicators of overall nutritional status.[30] The risk of malabsorption unique to the planned procedure dictates the significance of preoperative nutritional deficiencies.[16]

Patients with a history of gastroesophageal reflux disease (GERD) or findings consistent with gastrointestinal pathophysiology should be evaluated by a gastroenterologist in the preoperative period. Preoperative esophagogastroduodenoscopy (EGD) is frequently recommended for these patients to evaluate the presence of a hiatal hernia, Helicobacter pylori disease, Barrett esophagus, or pathologic lesions of the upper gastrointestinal tract.[31] The EGD may reveal a finding that affects the choice of weight loss procedure or dictates additional follow-up visits in the postoperative period.[31][32] The Bariatric Outcomes Longitudinal Database, a prospective registry of bariatric surgeries performed at centers of excellence, evaluated the evaluation or improvement of GERD symptoms after different weight loss procedures and found that the Roux-en-Y gastric bypass was more successful in decreasing GERD symptoms.[33] The presence of Barret esophagus, a precursor lesion of esophageal adenocarcinoma caused by poorly managed GERD, is a relative contraindication to sleeve gastrectomy; sleeve gastrectomy can worsen GERD and allow for the progression of Barret esophagus.[34]

Patients pursuing weight loss surgery should be evaluated for underlying endocrinopathies in the preoperative period. Unmanaged endocrinopathies such as type 2 diabetes, thyroid disease, and polycystic ovarian syndrome can negatively affect outcomes after weight loss surgery. Assessment of serum hemoglobin A1c, thyroid stimulating hormone, and androgen levels is recommended.[35] In particular, type 2 diabetes, a common comorbidity in patients with obesity, needs to be well controlled before proceeding with weight loss surgery to decrease perioperative risks such as poor wound healing.[36] An endocrinologist should manage diabetes that is longstanding or has proven refractory to medical therapy. To reduce intraoperative and postoperative risk, patients with diabetes mellitus should demonstrate a hemoglobin A1c of 6.5% to 7%, a fasting blood glucose <110 mg/dL, and a 2-hour postprandial glucose <140 mg/dL.[16][37]

Candidates for weight loss surgery should meet with a registered dietitian for a clinical nutrition evaluation in the preoperative period. The success of weight loss surgery hinges on modifying dietary habits; patients require a nutritional plan and access to an expert for assistance with questions or concerns.[29]

Preoperative psychosocial and behavioral assessment is strongly recommended for patients considering weight loss surgery. Patients with obesity frequently have underlying mood, eating, and behavioral disorders that, if left unidentified and unmanaged, negatively affect postoperative outcomes and overall weight loss.[38] Psychosocial assessment can also identify deficiencies and provide strategies for improving interpersonal relationships, support systems, and lifestyle behaviors to achieve and sustain weight loss after surgery.[39][29] 

Patients with obesity pursuing weight loss surgery should be informed of excess skin and tissue possibilities after weight loss. Body changes after extreme weight loss can challenge mental and emotional health and quality of life. Consultation with a plastic surgeon to discuss medical and surgical strategies to improve overall body image following extreme weight loss can mitigate these challenges.[40]

Patients with obesity are at significantly increased anesthesia-related risks. Patients considering weight loss surgery for severe obesity frequently present with known or undiagnosed respiratory conditions such as obstructive sleep apnea or hypoventilation syndrome of obesity.[41][42] Consultation with a pulmonologist is recommended in these cases. Patients with obstructive sleep apnea require CPAP therapy in the preoperative period for perioperative risk reduction.[43]  The recommended therapy for hypoventilation syndrome of obesity is preoperative weight loss. Preoperative weight loss also reduces the weight on the chest and abdominal walls, improving intraoperative ventilation, easing surgical access to the peritoneal cavity, and decreasing anesthesia-related risks. Despite this risk reduction, patients undergoing weight loss surgery frequently require postoperative admission to the intensive care unit and should be counseled as such.[41]

Preoperative weight loss should be discussed with all patients considering weight loss surgery, even absent obesity-related pulmonary conditions. The benefits of preoperative weight loss include improved respiratory function and reduced liver size; both contribute to a technically easier and better-tolerated surgery.[44][45]

Obesity is a risk factor for venous thromboembolic disease, and all patients considering weight loss surgery require a risk assessment for this disease process. In addition to obtaining a comprehensive medical history, risk calculators such as the Caprini, Aberdeen, Geneva, or IMPROVE scores can be used in different settings to quantify risk.[46][47][46] Patients at increased risk for venous thromboembolic disease can be anticoagulated in the perioperative period. Postoperative use of sequential compression devices is strongly advised. Inferior vena cava filters are not routinely recommended unless otherwise indicated; the risks often outweigh the benefits.[47][48][27]

Patients undergoing weight loss surgery should avoid pregnancy in the immediate preoperative period and for 12 to 18 months postoperatively. Alterations in nutrient absorption caused by weight loss surgery pose harm to the patient and potential fetus should pregnancy occur during this time frame. If a patient chooses to maintain a pregnancy after weight loss surgery, medically supervised weight gain is encouraged.[16]

Smoking cessation is necessary for all patients considering weight loss surgery; smoking cessation should occur a minimum of 6 weeks before the procedure and be maintained postoperatively.[16] Cigarette smoking increases the risk of many intraoperative and postoperative events, including poor wound healing, thromboembolic and cardiovascular events, and marginal ulcer formation.[49] The preoperative assessment must include conversations regarding the consequences of tobacco use on overall health and surgical outcomes.

The preoperative assessment should also discuss the financial consideration of weight loss surgery. To obtain insurance approval, patients must have a documented medical reason for weight loss surgery. The costs associated with weight loss surgery are significant and would greatly burden a patient without approved coverage.[16][30]

Before weight loss surgery, a thorough discussion of the risks, benefits, and alternatives to the procedure must be accomplished via the informed consent process. While all surgical procedures have some inherent risk, these risks are often significantly increased in the setting of obesity and its comorbid conditions.[30]

Clinical Significance

The preoperative assessment before weight loss surgery holds significant clinical importance for several reasons. 

Weight loss surgery is not appropriate for every patient with obesity. The preoperative assessment ensures that patients are suitable candidates for the procedure, have realistic expectations, and are committed to the behavioral and lifestyle changes required to achieve and sustain weight loss.

Obesity is frequently associated with comorbid conditions, such as hypertension, obstructive sleep apnea, cardiovascular disease, and type 2 diabetes. A comprehensive preoperative assessment plays a vital role in identifying and managing various comorbidities associated with obesity before weight loss surgery. This allows the interprofessional team to tailor the procedure and perioperative care to the patient's specific needs.

Patients with obesity undergoing weight loss surgery are at increased surgical risk over baseline. The preoperative assessment helps identify preexisting conditions that may negatively impact anesthesia, surgery, and postoperative recovery. Optimization of baseline health status by addressing underlying medical conditions decreases surgical risks and improves weight loss outcomes.

The preoperative assessment offers a valuable platform for patient education and counseling. It allows interprofessional healthcare team members to discuss the potential benefits, risks, and expected outcomes of weight loss surgery with the patient and their support system. Detailed discussions regarding dietary changes, postoperative care, and long-term lifestyle modifications are crucial for ensuring patient understanding, adherence, and overall success following the procedure.

Enhancing Healthcare Team Outcomes

An interprofessional team approach can significantly improve outcomes following weight loss surgery by promoting comprehensive care, coordination, and collaboration among healthcare professionals. A team of physicians, surgeons, dietitians, mental health professionals, nurses, and other relevant healthcare professionals should participate in the preoperative assessment of patients considering weight loss surgery. The team's combined expertise ensures a holistic assessment of physical health, mental health, nutritional status, and readiness for lifestyle changes.

Collaborative decision-making within the interprofessional team allows for individualized treatment and surgical planning. The unique perspective of each team member promotes dietary plans, exercise regimens, psychological support, and postoperative care strategies uniquely designed for each patient, optimizing the chances of successful patient outcomes. During the preoperative assessment phase, the interprofessional team can coordinate preoperative testing and consultations and implement strategies to reduce surgical risks.

An interprofessional team approach improves outcomes following weight loss surgery by facilitating comprehensive patient evaluation, individualized treatment planning, enhanced perioperative management, multidisciplinary support, continuity of care, and patient education. By leveraging multiple healthcare professionals' collective expertise and collaboration, patients can receive comprehensive care and support throughout their weight loss journey, leading to improved outcomes and long-term success. 



Apovian CM. Obesity: definition, comorbidities, causes, and burden. The American journal of managed care. 2016 Jun:22(7 Suppl):s176-85     [PubMed PMID: 27356115]


Hales CM, Fryar CD, Carroll MD, Freedman DS, Ogden CL. Trends in Obesity and Severe Obesity Prevalence in US Youth and Adults by Sex and Age, 2007-2008 to 2015-2016. JAMA. 2018 Apr 24:319(16):1723-1725. doi: 10.1001/jama.2018.3060. Epub     [PubMed PMID: 29570750]


Seravalle G, Grassi G. Obesity and hypertension. Pharmacological research. 2017 Aug:122():1-7. doi: 10.1016/j.phrs.2017.05.013. Epub 2017 May 19     [PubMed PMID: 28532816]


Ortega FB, Lavie CJ, Blair SN. Obesity and Cardiovascular Disease. Circulation research. 2016 May 27:118(11):1752-70. doi: 10.1161/CIRCRESAHA.115.306883. Epub     [PubMed PMID: 27230640]


Wadden TA, Tronieri JS, Butryn ML. Lifestyle modification approaches for the treatment of obesity in adults. The American psychologist. 2020 Feb-Mar:75(2):235-251. doi: 10.1037/amp0000517. Epub     [PubMed PMID: 32052997]


Ryan DH, Kahan S. Guideline Recommendations for Obesity Management. The Medical clinics of North America. 2018 Jan:102(1):49-63. doi: 10.1016/j.mcna.2017.08.006. Epub     [PubMed PMID: 29156187]


Ikramuddin S, Korner J, Lee WJ, Connett JE, Inabnet WB, Billington CJ, Thomas AJ, Leslie DB, Chong K, Jeffery RW, Ahmed L, Vella A, Chuang LM, Bessler M, Sarr MG, Swain JM, Laqua P, Jensen MD, Bantle JP. Roux-en-Y gastric bypass vs intensive medical management for the control of type 2 diabetes, hypertension, and hyperlipidemia: the Diabetes Surgery Study randomized clinical trial. JAMA. 2013 Jun 5:309(21):2240-9. doi: 10.1001/jama.2013.5835. Epub     [PubMed PMID: 23736733]

Level 1 (high-level) evidence


Weir CB, Jan A. BMI Classification Percentile And Cut Off Points. StatPearls. 2023 Jan:():     [PubMed PMID: 31082114]


Bray MS, Loos RJ, McCaffery JM, Ling C, Franks PW, Weinstock GM, Snyder MP, Vassy JL, Agurs-Collins T, Conference Working Group. NIH working group report-using genomic information to guide weight management: From universal to precision treatment. Obesity (Silver Spring, Md.). 2016 Jan:24(1):14-22. doi: 10.1002/oby.21381. Epub     [PubMed PMID: 26692578]


Heymsfield SB, Wadden TA. Mechanisms, Pathophysiology, and Management of Obesity. The New England journal of medicine. 2017 Jan 19:376(3):254-266. doi: 10.1056/NEJMra1514009. Epub     [PubMed PMID: 28099824]


Stefater MA, Wilson-Pérez HE, Chambers AP, Sandoval DA, Seeley RJ. All bariatric surgeries are not created equal: insights from mechanistic comparisons. Endocrine reviews. 2012 Aug:33(4):595-622. doi: 10.1210/er.2011-1044. Epub 2012 May 1     [PubMed PMID: 22550271]

Level 3 (low-level) evidence


Angrisani L, Santonicola A, Iovino P, Vitiello A, Zundel N, Buchwald H, Scopinaro N. Bariatric Surgery and Endoluminal Procedures: IFSO Worldwide Survey 2014. Obesity surgery. 2017 Sep:27(9):2279-2289. doi: 10.1007/s11695-017-2666-x. Epub     [PubMed PMID: 28405878]

Level 3 (low-level) evidence


English WJ, DeMaria EJ, Hutter MM, Kothari SN, Mattar SG, Brethauer SA, Morton JM. American Society for Metabolic and Bariatric Surgery 2018 estimate of metabolic and bariatric procedures performed in the United States. Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery. 2020 Apr:16(4):457-463. doi: 10.1016/j.soard.2019.12.022. Epub 2020 Jan 3     [PubMed PMID: 32029370]


Arterburn DE, Courcoulas AP. Bariatric surgery for obesity and metabolic conditions in adults. BMJ (Clinical research ed.). 2014 Aug 27:349():g3961. doi: 10.1136/bmj.g3961. Epub 2014 Aug 27     [PubMed PMID: 25164369]


Shimizu H, Timratana P, Schauer PR, Rogula T. Review of Metabolic Surgery for Type 2 Diabetes in Patients with a BMI { 35 kg/m(2). Journal of obesity. 2012:2012():147256. doi: 10.1155/2012/147256. Epub 2012 Jun 5     [PubMed PMID: 22720136]


Mechanick JI, Youdim A, Jones DB, Timothy Garvey W, Hurley DL, Molly McMahon M, Heinberg LJ, Kushner R, Adams TD, Shikora S, Dixon JB, Brethauer S. 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. Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery. 2013 Mar-Apr:9(2):159-91. doi: 10.1016/j.soard.2012.12.010. Epub 2013 Jan 19     [PubMed PMID: 23537696]

Level 1 (high-level) evidence


Abdullah A, Wolfe R, Stoelwinder JU, de Courten M, Stevenson C, Walls HL, Peeters A. The number of years lived with obesity and the risk of all-cause and cause-specific mortality. International journal of epidemiology. 2011 Aug:40(4):985-96. doi: 10.1093/ije/dyr018. Epub 2011 Feb 27     [PubMed PMID: 21357186]

Level 2 (mid-level) evidence


Thenappan A, Nadler E. Bariatric Surgery in Children: Indications, Types, and Outcomes. Current gastroenterology reports. 2019 Apr 25:21(6):24. doi: 10.1007/s11894-019-0691-8. Epub 2019 Apr 25     [PubMed PMID: 31025124]


Pratt JSA, Browne A, Browne NT, Bruzoni M, Cohen M, Desai A, Inge T, Linden BC, Mattar SG, Michalsky M, Podkameni D, Reichard KW, Stanford FC, Zeller MH, Zitsman J. ASMBS pediatric metabolic and bariatric surgery guidelines, 2018. Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery. 2018 Jul:14(7):882-901. doi: 10.1016/j.soard.2018.03.019. Epub 2018 Mar 23     [PubMed PMID: 30077361]


Lamoshi A, Chernoguz A, Harmon CM, Helmrath M. Complications of bariatric surgery in adolescents. Seminars in pediatric surgery. 2020 Feb:29(1):150888. doi: 10.1016/j.sempedsurg.2020.150888. Epub 2020 Jan 20     [PubMed PMID: 32238287]


Giordano S, Victorzon M. Bariatric surgery in elderly patients: a systematic review. Clinical interventions in aging. 2015:10():1627-35. doi: 10.2147/CIA.S70313. Epub 2015 Oct 13     [PubMed PMID: 26508845]

Level 1 (high-level) evidence


Nelson EC, Landgraf JM, Hays RD, Wasson JH, Kirk JW. The functional status of patients. How can it be measured in physicians' offices? Medical care. 1990 Dec:28(12):1111-26     [PubMed PMID: 2250496]


Junek ML, Jones A, Heckman G, Demers C, Griffith LE, Costa AP. The predictive utility of functional status at discharge: a population-level cohort analysis. BMC geriatrics. 2022 Jan 3:22(1):8. doi: 10.1186/s12877-021-02652-6. Epub 2022 Jan 3     [PubMed PMID: 34979946]


Pechman DM, Muñoz Flores F, Kinkhabwala CM, Salas R, Berk RH, Weithorn D, Camacho DR. Bariatric surgery in the elderly: outcomes analysis of patients over 70 using the ACS-NSQIP database. Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery. 2019 Nov:15(11):1923-1932. doi: 10.1016/j.soard.2019.08.011. Epub 2019 Aug 23     [PubMed PMID: 31611184]

Level 2 (mid-level) evidence


Doyle DJ, Hendrix JM, Garmon EH. American Society of Anesthesiologists Classification. StatPearls. 2023 Jan:():     [PubMed PMID: 28722969]


Stahl JM, Malhotra S. Obesity Surgery Indications and Contraindications. StatPearls. 2023 Jan:():     [PubMed PMID: 30020657]


Rowland SP, Dharmarajah B, Moore HM, Lane TR, Cousins J, Ahmed AR, Davies AH. Inferior vena cava filters for prevention of venous thromboembolism in obese patients undergoing bariatric surgery: a systematic review. Annals of surgery. 2015 Jan:261(1):35-45. doi: 10.1097/SLA.0000000000000621. Epub     [PubMed PMID: 25599325]

Level 1 (high-level) evidence


King WC, Chen JY, Courcoulas AP, Dakin GF, Engel SG, Flum DR, Hinojosa MW, Kalarchian MA, Mattar SG, Mitchell JE, Pomp A, Pories WJ, Steffen KJ, White GE, Wolfe BM, Yanovski SZ. Alcohol and other substance use after bariatric surgery: prospective evidence from a U.S. multicenter cohort study. Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery. 2017 Aug:13(8):1392-1402. doi: 10.1016/j.soard.2017.03.021. Epub 2017 Mar 31     [PubMed PMID: 28528115]


Schlottmann F, Nayyar A, Herbella FAM, Patti MG. Preoperative Evaluation in Bariatric Surgery. Journal of laparoendoscopic & advanced surgical techniques. Part A. 2018 Aug:28(8):925-929. doi: 10.1089/lap.2018.0391. Epub 2018 Jul 13     [PubMed PMID: 30004270]


Mechanick JI, Youdim A, Jones DB, Garvey WT, Hurley DL, McMahon MM, Heinberg LJ, Kushner R, Adams TD, Shikora S, Dixon JB, Brethauer S, American Association of Clinical Endocrinologists, Obesity Society, American Society for Metabolic & Bariatric Surgery. 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, Md.). 2013 Mar:21 Suppl 1(0 1):S1-27. doi: 10.1002/oby.20461. Epub     [PubMed PMID: 23529939]


Moulla Y, Lyros O, Mehdorn M, Lange U, Hamade H, Thieme R, Hoffmeister A, Feisthammel J, Blüher M, Jansen-Winkeln B, Gockel I, Dietrich A. Preoperative Upper-GI Endoscopy Prior to Bariatric Surgery: Essential or Optional? Obesity surgery. 2020 Jun:30(6):2076-2084. doi: 10.1007/s11695-020-04485-5. Epub     [PubMed PMID: 32096015]


Wolter S, Duprée A, Miro J, Schroeder C, Jansen MI, Schulze-Zur-Wiesch C, Groth S, Izbicki J, Mann O, Busch P. Upper Gastrointestinal Endoscopy prior to Bariatric Surgery-Mandatory or Expendable? An Analysis of 801 Cases. Obesity surgery. 2017 Aug:27(8):1938-1943. doi: 10.1007/s11695-017-2622-9. Epub     [PubMed PMID: 28243860]

Level 3 (low-level) evidence


Pallati PK, Shaligram A, Shostrom VK, Oleynikov D, McBride CL, Goede MR. Improvement in gastroesophageal reflux disease symptoms after various bariatric procedures: review of the Bariatric Outcomes Longitudinal Database. Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery. 2014 May-Jun:10(3):502-7. doi: 10.1016/j.soard.2013.07.018. Epub 2013 Aug 29     [PubMed PMID: 24238733]

Level 2 (mid-level) evidence


Davrieux CF, Palermo M, Nedelcu M, Nocca D. Reflux After Sleeve Gastrectomy: An Update. Journal of laparoendoscopic & advanced surgical techniques. Part A. 2021 Sep:31(9):978-982. doi: 10.1089/lap.2021.0478. Epub 2021 Aug 12     [PubMed PMID: 34388044]


Garvey WT, Mechanick JI, Brett EM, Garber AJ, Hurley DL, Jastreboff AM, Nadolsky K, Pessah-Pollack R, Plodkowski R, Reviewers of the AACE/ACE Obesity Clinical Practice Guidelines. AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY COMPREHENSIVE CLINICAL PRACTICE GUIDELINES FOR MEDICAL CARE OF PATIENTS WITH OBESITY. Endocrine practice : official journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists. 2016 Jul:22 Suppl 3():1-203. doi: 10.4158/EP161365.GL. Epub 2016 May 24     [PubMed PMID: 27219496]

Level 1 (high-level) evidence


Swoboda L, Held J. Impaired wound healing in diabetes. Journal of wound care. 2022 Oct 2:31(10):882-885. doi: 10.12968/jowc.2022.31.10.882. Epub     [PubMed PMID: 36240794]


Handelsman Y, Bloomgarden ZT, Grunberger G, Umpierrez G, Zimmerman RS, Bailey TS, Blonde L, Bray GA, Cohen AJ, Dagogo-Jack S, Davidson JA, Einhorn D, Ganda OP, Garber AJ, Garvey WT, Henry RR, Hirsch IB, Horton ES, Hurley DL, Jellinger PS, Jovanovič L, Lebovitz HE, LeRoith D, Levy P, McGill JB, Mechanick JI, Mestman JH, Moghissi ES, Orzeck EA, Pessah-Pollack R, Rosenblit PD, Vinik AI, Wyne K, Zangeneh F. American association of clinical endocrinologists and american college of endocrinology - clinical practice guidelines for developing a diabetes mellitus comprehensive care plan - 2015. Endocrine practice : official journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists. 2015 Apr:21 Suppl 1(Suppl 1):1-87. doi: 10.4158/EP15672.GL. Epub     [PubMed PMID: 25869408]

Level 1 (high-level) evidence


Pull CB. Current psychological assessment practices in obesity surgery programs: what to assess and why. Current opinion in psychiatry. 2010 Jan:23(1):30-6. doi: 10.1097/YCO.0b013e328334c817. Epub     [PubMed PMID: 19926994]

Level 3 (low-level) evidence


Fabricatore AN, Crerand CE, Wadden TA, Sarwer DB, Krasucki JL. How do mental health professionals evaluate candidates for bariatric surgery? Survey results. Obesity surgery. 2006 May:16(5):567-73     [PubMed PMID: 16687023]

Level 3 (low-level) evidence


Gunnarson GL, Frøyen JK, Sandbu R, Thomsen JB, Hjelmesæth J. Plastic surgery after bariatric surgery. Tidsskrift for den Norske laegeforening : tidsskrift for praktisk medicin, ny raekke. 2015 Jun 16:135(11):1044-9. doi: 10.4045/tidsskr.14.0814. Epub 2015 Jun 16     [PubMed PMID: 26080780]


Rasmussen JJ, Fuller WD, Ali MR. Sleep apnea syndrome is significantly underdiagnosed in bariatric surgical patients. Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery. 2012 Sep-Oct:8(5):569-73. doi: 10.1016/j.soard.2011.06.021. Epub 2011 Jul 24     [PubMed PMID: 21925966]


Fritscher LG, Mottin CC, Canani S, Chatkin JM. Obesity and obstructive sleep apnea-hypopnea syndrome: the impact of bariatric surgery. Obesity surgery. 2007 Jan:17(1):95-9     [PubMed PMID: 17355775]


Jehan S, Zizi F, Pandi-Perumal SR, Wall S, Auguste E, Myers AK, Jean-Louis G, McFarlane SI. Obstructive Sleep Apnea and Obesity: Implications for Public Health. Sleep medicine and disorders : international journal. 2017:1(4):. pii: 00019. Epub 2017 Dec 12     [PubMed PMID: 29517065]


Fris RJ. Preoperative low energy diet diminishes liver size. Obesity surgery. 2004 Oct:14(9):1165-70     [PubMed PMID: 15527628]


Edholm D, Kullberg J, Haenni A, Karlsson FA, Ahlström A, Hedberg J, Ahlström H, Sundbom M. Preoperative 4-week low-calorie diet reduces liver volume and intrahepatic fat, and facilitates laparoscopic gastric bypass in morbidly obese. Obesity surgery. 2011 Mar:21(3):345-50. doi: 10.1007/s11695-010-0337-2. Epub     [PubMed PMID: 21181291]


Pandor A, Tonkins M, Goodacre S, Sworn K, Clowes M, Griffin XL, Holland M, Hunt BJ, de Wit K, Horner D. Risk assessment models for venous thromboembolism in hospitalised adult patients: a systematic review. BMJ open. 2021 Jul 29:11(7):e045672. doi: 10.1136/bmjopen-2020-045672. Epub 2021 Jul 29     [PubMed PMID: 34326045]

Level 1 (high-level) evidence


Almarshad FM, Almegren M, Alshuaibi T, Alobaodi N, Almutawa A, Basunbl H, AlGahtani F, Al Rawahi B. Thromboprophylaxis after bariatric surgery. Blood research. 2020 Mar:55(1):44-48. doi: 10.5045/br.2020.55.1.44. Epub 2020 Mar 30     [PubMed PMID: 32269974]


Martin KA, Lee CR, Farrell TM, Moll S. Oral Anticoagulant Use After Bariatric Surgery: A Literature Review and Clinical Guidance. The American journal of medicine. 2017 May:130(5):517-524. doi: 10.1016/j.amjmed.2016.12.033. Epub 2017 Feb 1     [PubMed PMID: 28159600]


Beran A, Shaear M, Al-Mudares S, Sharma I, Matar R, Al-Haddad M, Salame M, Portela R, Clapp B, Dayyeh BKA, Ghanem OM. Predictors of marginal ulcer after gastric bypass: a systematic review and meta-analysis. Journal of gastrointestinal surgery : official journal of the Society for Surgery of the Alimentary Tract. 2023 Jun:27(6):1066-1077. doi: 10.1007/s11605-023-05619-7. Epub 2023 Feb 16     [PubMed PMID: 36795250]

Level 1 (high-level) evidence