Torgeir T. Søvik, MD; Erlend T. Aasheim, MD, PhD; Osama Taha, MD; My Engström, RN; Morten W. Fagerland, MSc, PhD; Sofia Björkman, RD; Jon Kristinsson, MD, PhD; Kåre I. Birkeland, MD, PhD; Tom Mala, MD, PhD; Torsten Olbers, MD, PhD
Gastric bypass and duodenal switch are currently performed bariatric surgical procedures. Uncontrolled studies suggest that duodenal switch induces greater weight loss than gastric bypass.
To determine whether duodenal switch leads to greater weight loss and more favorable improvements in cardiovascular risk factors and quality of life than gastric bypass.
Randomized, parallel-group trial. (ClinicalTrials.gov registration number: NCT00327912)
2 academic medical centers (1 in Norway and 1 in Sweden).
60 participants with a body mass index (BMI) between 50 and 60 kg/m2.
Gastric bypass (n = 31) or duodenal switch (n = 29).
The primary outcome was the change in BMI after 2 years. Secondary outcomes included anthropometric measures; concentrations of blood lipids, glucose, insulin, C-reactive protein, and vitamins; and health-related quality of life and adverse events.
Fifty-eight of 60 participants (97%) completed the study. The mean reductions in BMI were 17.3 kg/m2 (95% CI, 15.7 to 19.0 kg/m2) after gastric bypass and 24.8 kg/m2 (CI, 23.0 to 26.5 kg/m2) after duodenal switch (mean between-group difference, 7.44 kg/m2 [CI, 5.24 to 9.64 kg/m2]; P < 0.001). Total cholesterol concentration decreased by 0.24 mmol/L (CI, −0.03 to 0.50 mmol/L) (9.27 mg/dL [CI, −1.16 to 19.3 mg/dL]) after gastric bypass and 1.07 mmol/L (CI, 0.79 to 1.35 mmol/L) (41.3 mg/dL [CI, 30.5 to 52.1 mg/dL]) after duodenal switch (mean between-group difference, 0.83 mmol/L [CI, 0.48 to 1.18 mmol/L]; 32.0 mg/dL [CI, 18.5 to 45.6 mg/dL]; P < 0.001). Reductions in low-density lipoprotein cholesterol concentration, anthropometric measures, fat mass, and fat-free mass were also greater after duodenal switch (P ≤ 0.010 for each between-group comparison). Both groups had reductions in blood pressure and mean concentrations of glucose, insulin, and C-reactive protein, with no between-group differences. The duodenal switch group, but not the gastric bypass group, had reductions in concentrations of vitamin A and 25-hydroxyvitamin D. Most Short Form-36 Health Survey dimensional scores improved in both groups, with greater improvement in 1 of 8 domains (bodily pain) after gastric bypass. From surgery until 2 years, 10 participants (32%) had adverse events after gastric bypass and 18 (62%) after duodenal switch (P = 0.021). Adverse events related to malnutrition occurred only after duodenal switch.
Clinical experience was greater with gastric bypass than with duodenal switch at the study centers.
Duodenal switch surgery was associated with greater weight loss, greater reductions of total and low-density lipoprotein cholesterol concentrations, and more adverse events. Improvements in other cardiovascular risk factors and quality of life were similar after both procedures.
South-Eastern Norway Regional Health Authority.
Two types of bariatric surgery are commonly used to treat severe obesity: gastric bypass and duodenal switch. Few controlled clinical trials of these procedures have been reported.
Patients with a body mass index between 50 and 60 kg/m2 were randomly assigned to undergo gastric bypass or duodenal switch. After 2 years, duodenal switch resulted in significantly greater reduction in body mass index than gastric bypass but was more commonly associated with adverse events. Dietary factors, quality of life, and cardiovascular markers varied with each procedure.
The effect of surgical experience on outcomes was not assessed.
Patients benefited from both types of bariatric surgery. The choice of procedure should be individualized.
Bowel limb lengths for gastric bypass: alimentary limb, 150 cm; biliopancreatic limb, 50 cm; and common channel, variable length. Bowel limb lengths for duodenal switch: alimentary limb, 200 cm; biliopancreatic limb, variable length; and common channel, 100 cm. Figures by Ole-Jacob Berge, MD, and reproduced from reference 25 with permission.
BMI = body mass index.
Estimated postsurgery values are expected means from the linear mixed-effects models. Error bars indicate 95% CIs. P < 0.001 for between-group changes. BMI = body mass index.
Appendix Table 1.
Estimated postsurgery values are expected means from the linear mixed-effects models. Error bars indicate 95% CIs. To convert cholesterol values to mg/dL, divide by 0.0259. To convert triglyceride values to mg/dL, divide by 0.0113. HDL = high-density lipoprotein; LDL = low-density lipoprotein.
* P < 0.001 for between-group changes.
† P = 0.78 for between-group changes.
Estimated postsurgery values are expected means from the linear mixed-effects models. Error bars indicate 95% CIs. Values for participants who used insulin were excluded (1 in the gastric bypass group at all time points and 1 in the duodenal switch group at baseline). To convert glucose values to mg/dL, divide by 0.0555. To convert insulin values to pmol/L, multiply by 6. To convert CRP values to nmol/L, multiply by 9.524. CRP = C-reactive protein.
* P = 0.077 for between-group changes.
† P = 0.123 for between-group changes.
‡ P = 0.94 for between-group changes.
Appendix Table 2.
Estimated postsurgery values are expected means from the linear mixed-effects models; a score of 0 represents worst possible health and 100 represents best possible health. Estimated postsurgery values are expected means from the linear mixed-effects models. BP = bodily pain; GH = general health perceptions; MH = general mental health; PF = physical functioning; RE = role limitations due to emotional problems; RP = role limitations due to physical health problems; SF = social functioning; SF-36 = Short Form-36 Health Survey; VT = vitality.
Appendix Table 3.
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John G Kral
SUNY Downstate Medical Center
October 9, 2011
Ledtter to the Editor: Bypassing Bariatric Surgery and Editorial Evidence
The journal published a rarity: an ethical, scientific, randomized, trial of bariatric surgery (1) exhibiting equipoise: the two operations are similar, in contrast with randomizations between operations with different mechanisms and effects (2) or between any operation and "medical" care (3), although long-term data demonstrate superiority of the one operation. One might question equality of the two hospitals, equivalency of the teams' learning curves, follow-up schedules lacking postoperative "dietitian and surgeon" visits during the important 12-24 months after bypass operations in superobese patients and drawing conclusions after only 2 years when slopes of the mean BMI diverge in groups with different follow-up rates, and particularly too early to evaluate the most valuable benefits of these operations. However, the accompanying Editorial (4) raises more serious questions:
Is it accurate or "evidence-based" to portray superobese patients as "metabolically normal", "healthy" or "near -normal"?
Should all malabsorptive operations be branded as "inherently dangerous"? Gastrointestinal surgery is "dangerous" yet meets risk-benefit and cost-benefit criteria or else would not be allowed?
Can outcomes of treatments of superobese patients be evaluated after only 2 years? No 2-year evidence supports stating: "greater weight loss does not seem to change the anticipated long-term outcomes for bariatric surgery". Predictions before weight and compensatory adaptive mechanisms have stabilized are unfounded. There is no evidence that "Many patients are well-adapted to their obesity"; neither superobese patients in general nor 'bariatric surgery' patients. The editorial criticizes the "low methodological quality" of studies of bariatric surgery and requests "good evidence", yet describes a rare complication as "particularly worrisome for these young women" based on one case-report (5). Not to trivialize this, but the complication is rare and easily prevented by standard of care following authoritative guidelines (editorial refs 3 and 4).
"Complications are serious" and "may take years to manifest" but it is not accurate that "the true complication rate over the lifetime of these young patients can be expected to be formidable". Both operations have been performed for 35 years with large series exceeding 15 years, including two with offspring of mothers with the potentially more "dangerous" of the operations followed for 2-24 years. The complications are known, germane to gastrointestinal surgery, but most important: They are easily preventable by competent follow-up care and are substantially easier to treat effectively than superobesity or less extreme forms of obesity. In the final analysis patients must decide whether effects of these operations, beneficial or adverse, outweigh their own suffering with their disease. Responsible physicians must provide the best available understandable evidence to lay patients.
1. Sovik TT et al. Weight loss, cardiovascular risk factors and quality of life after gastric bypass and duodenal switch. Ann Intern Med 2011;155: 281-91
2. Kral JG. Psychosurgery for obesity. Obes Facts 2009;2:339-41
3. Kral JG et al. Flaws in methods of evidence-based medicine may adversely affect public health directives. Surgery 2005;137:279-84
4. Livingston EH. Primum Non Nocere. Ann Intern Med 2011;155:329-330.
5. Huerta S, Rogers LM, Li Z, Heber D, Liu C, Livingston EH. Vitamin A deficiency an a newborn resulting from maternal hypovitaminosis A after biliopancreatic diversion for the treatment of morbid obesity. Am J Clin Nutr. 2002:76:426-9.
October 12, 2011
Unidentified flaws in both original paper and editorial
Sovik and colleagues (1) are to be congratulated on performing one of the few RCTs comparing bariatric surgical procedures, but their paper has serious flaws which were not identified in the accompanying editorial (2) nor the subsequent reports in other journals(3) and specialist websites.
What Sovik's data actually illustrates is that if duodenal switch (DS) is performed on randomly (instead of carefully) selected patients by relatively inexperienced surgeons and if patients are then given sub- optimal vitamin replacement (more suited to a short-limb Roux-en-Y gastric bypass) and infrequent follow-up, post-operative problems are not uncommon. In fact with this study design it was remarkable that so few adverse events were seen.
Our experience of 125 DS patients followed for up to 5 years(4) confirmed Sovik's report that the DS is indeed associated with reversible nutritional deficiencies (particularly vitamin D). However, we and others recognize that the DS is not a universally applicable operation because it requires an exceptional level of post-operative patient compliance. Few patients are capable of this and without careful selection problems can occur, particularly if, as in this study, their nutrition is only being monitored once every 6-12 months during the crucial mid-late post- operative period. The very notion of randomizing potentially non-compliant patients to a DS is flawed.
Sovik previously reported (5) that most of the difference in complication rates between the two operations occurred in the first 30 days after surgery and was related to technical complications (including an unusually high leak/abscess rate of 10.3%) or complications attributable to the DS's prolonged operative time. Their current paper confirms this to be the case as only an additional 4 gastric bypass and 7 DS patients developed complications between 30 days and 1 year post-op. Although not statistically significant, the most common adverse event in the DS group was vomiting (3/7), which is understandable given the extremely tight (30-32F) sleeve gastrectomy the authors performed. In year two, a further 5 gastric bypass patients developed adverse events, compared to just 3 DS patients (two due to trauma rather than surgery).
The DS is a technically challenging procedure and mandates a strict post-operative regime with intensive support from the bariatric team. It is clear that to keep the frequency of adverse events to a minimum in the early and late post-operative periods the DS should only be offered to carefully selected patients treated in specialist centres. Sovik's paper simply confirms this and adds little more.
DD Kerrigan CJ Magee AI Mitchell
1. Sovik TT, Aasheim ET, Taha O, Engstrom M, Fagerland MW, Bjorkman S, et al. Weight loss, cardiovascular risk factors, and quality of life after gastric bypass and duodenal switch: a randomized trial. Ann Intern Med. 2011;155(5):281-91.
2. Livingston EH. Primum non nocere. Ann Intern Med. 2011;155(5):329-30.
3. BMJ. Short Cuts: Duodenal Switch is a poor choice in super obese adults. British Medical Journal. 2011.
4. Magee CJ, Barry J, Brocklehurst J, Javed S, Macadam R, Kerrigan DD. Outcome of laparoscopic duodenal switch for morbid obesity. Br J Surg. 2011;98(1):79-84.
5. Sovik TT, Taha O, Aasheim ET, Engstrom M, Kristinsson J, Bjorkman S, et al. Randomized clinical trial of laparoscopic gastric bypass versus laparoscopic duodenal switch for superobesity. Br J Surg. 2010;97(2):160- 6.
Fernando B Bonanni MD FACS FASMBS
Abington Memorial Hospital
October 16, 2011
Duodenal Switch: Experience counts
Letter to the Editor,
Those of us who have dedicated ourselves to offering the entire arsenal in weight loss surgery have come to understand the important role the Duodenal Switch has in the Super Obese patient and in the future of Bariatric Surgery.
The data provided reveals greater weight loss in DS patients resulting in reduction of 25 BMI units compared to 17 in the GBP. (p value of < .001) Improvement in cholesterol in DS patients was greater. (p value of < .0001). 26% of GBP group were still morbidly obese as compared to none in the DS group. Early and late post-operative morbidity was not statistically significant. The authors comment that there is a tendency toward protein malnutrition in the DS patient.
The authors offer an unusually aggressive construction of the DS. The Sleeve component is more aggressive than a standard VSG. The average bougie size in a VSG is 34 to 38 F Bougie. The Sleeve component of a standard DS procedure is usually created larger than a standard sleeve anticipating significant contribution to weight loss by the diversionary component of the procedure. A Common Channel of 100 cm plus an aggressive sleeve is a set up for excessive weight loss and serious sequale of protein malnutrition. Intense nutritional follow up with specific instruction on adequate protein supplementation, hydration, and vitamin supplement is paramount. Most programs require that Vitamins A D E K Fe Ca++, Zinc, and protein are supplemented and followed closely.
Persistent morbid obesity in 26% of GBP patients underscores the shortcomings of the GBP procedure in the super obese. A predictable recidivism rate in GBP of 8 - 23 % is well known to start at post op two years. It is probable that the majority of the GBP patients in this study will regain weight and comorbid disease will return. The construction of the DS in this study will lead to predictable and serious nutritional consequences in the DS patients in this study.
The DS is superior in the Super Obese. We cannot continue to ignore inadequate weight loss and high rate of recidivism in the super obese patient after GBP. Experience and a comprehensive nutrition program achieve safe results. Standardization of procedures and nutritional protocol are necessary to study procedures accurately.
Fernando B. Bonanni Jr. MD FACS, FASMBS Director, Institute of Metabolic and Bariatric Surgery Abington Memorial Hospital
Department of Experimental Medicine, Sapienza University of Rome
October 21, 2011
Weight loss, cardiovascular risk factors, and quality of life after gastric bypass and duodenal switch
TO THE EDITOR We read with great interest the recent article by Sovik and colleagues (1) regarding the change of weight, cardiovascular risk factors and quality of life 2 years after gastric bypass and duodenal switch. However, we have some comments on the paper. The selection criteria for different bariatric techniques are not well defined and are usually based on psychiatric statement, body weight and relative surgical risk. The authors didn't clarify if the patients underwent psychiatric assessment, which were the criteria used for the eligibility of the bariatric surgery options. As clearly discussed by Sovik and colleagues, duodenal switch surgery should be restricted to well -informed super obese patients who are likely to adhere to clinical follow -up. As a consequence, the patients should be carefully selected instead of being randomized. In this case the randomization procedure raises important ethical concerns that may be overcome with case-control study design (2). Since fat distribution more than the total amount of fat is critical in defining cardiovascular risk and insulin resistance, an evaluation of fat distribution in both visceral and peripheral sites through either a surrogate marker like waist to hip ratio or direct measurements of the different body compartments by DXA analysis of body composition is advisable in order to assess the quality of weight loss (3). Furthermore, the calculation of the HOMA-IR index would have more likely better characterized the changes of insulin resistance rather than fasting glucose and insulin serum concentrations values. Faecal excretion of cholesterol is one of the main mechanisms through which malabsorptive techniques can reduce circulating total, LDL and HDL cholesterol (4). The authors show a greater LDL reduction after duodenal switch, but the reported increase of HDL cholesterol appears not significant; on the contrary, the HDL cholesterol values are clearly increased in the gastric bypass group. Thus, calculated indices such as total cholesterol/HDL cholesterol ratio would have been appropriate. It is difficult to explain why both gastric bypass and duodenal switch patients showed a superimposable increase of PTH whilst only duodenal switch patients were vitamin D deficient. Whether increased PTH levels are relevant to future skeletal health is still an open question. Recent epidemiologic and clinical studies showed that obesity may not be protective for osteoporosis and weight reduction per se causes bone loss (5). Therefore, an assessment of bone mineral density modifications after surgery-induced weight loss is advisable. Finally, the authors did not account for confounding like sex and age including menopause and exposure to oral contraceptives in the female subgroup.
1. Sovik TT, Aasheim ET, Taha O, Engstrom M, Fagerland MW, Bjorkman S, Kristinsson J, Birkeland KI, Mala T, Olbers T. Weight loss, cardiovascular risk factors, and quality of life after gastric bypass and duodenal switch : a randomized trial. Ann Intern Med. 2011 Sep 6;155(5):281-91
2. Lubrano C, Mariani S, Badiali M, Cuzzolaro M, Barbaro G, Migliaccio S, Genovesi G, Rossi F, Celanetti M, Fiore D, Pandolfo MM, Specchia P, Spera G. Metabolic or bariatric surgery? Long-term effects of malabsorptive vs restrictive bariatric techniques on body composition and cardiometabolic risk factors. Int J Obes (Lond). 2010 Sep;34(9):1404-14
3. Bays HE, Laferr?re B, Dixon J, Aronne L, Gonzalez-Campoy JM, Apovian C, Wolfe BM; Adiposopathy and Bariatric Surgery Working Group.Adiposopathy and bariatric surgery: is 'sick fat' a surgical disease? Int J Clin Pract. 2009 Sep; 63(9):1285-300.
4. Corradini SG, Eramo A, Lubrano C, Spera G, Cornoldi A, Grossi A et al. Comparison of changes in lipid profile after bilio-intestinal bypass and gastric banding in patients with morbid obesity. Obes Surg 2005; 15: 367- 377.
5. Greco EA, Fornari R, Rossi F, Santiemma V, Prossomariti G, Annoscia C, Aversa A, Brama M, Marini M, Donini LM, Spera G, Lenzi A, Lubrano C, Migliaccio S. Is obesity protective for osteoporosis? Evaluation of bone mineral density in individuals with high body mass index. Int J Clin Pract. 2010 May; 64(6):817-20.
Tor I., Karlsen, PhD-student, Joran Hjelmesaeth
Morbid Obesity Center, Vestfold Hopital Trust, Norway
November 11, 2011
Quality of life assessment
We read with interest Sovik et al's report on the well performed randomized controlled trial comparing the effects of gastric bypass and duodenal switch . From the observed changes in the 8 sub-scales of health reated quality of life (HRQL)-questionnaire SF-36, the authors conclude that the two procedures had a similar effect on quality of life. We wish to suggest that this conclusion is questionable.
Søvik TT, Aasheim ET, Taha O, et al. Weight Loss, Cardiovascular Risk Factors, and Quality of Life After Gastric Bypass and Duodenal Switch: A Randomized Trial. Ann Intern Med. 2011;155:281–291. doi: 10.7326/0003-4819-155-5-201109060-00005
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Published: Ann Intern Med. 2011;155(5):281-291.
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