Clinical Practice Assessment. Bariatric Surgery

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1 Clinical Practice Assessment Bariatric Surgery Clinical Question: In patients with obesity, do those who undergo a bariatric surgery procedure, compared to those managed medically, have better outcomes? Bottom Line: Surgery appears to be a clinically effective and cost-effective intervention for moderately to severely obese people compared to non-surgical interventions. Certain procedures produce greater weight loss, but data are limited. The evidence on safety is even less clear. Due to limited evidence and poor quality of the trials, caution is required when interpreting comparative safety and effectiveness. [link to Cochrane Plain Language Summary] EF92DBC9CD97DCFB6B26223E753C639.d01t02 Synopsis: The Cochrane Systematic Review included 26 studies (23 RCTs; 1 controlled and 2 uncontrolled cohort studies). Most were of poor quality, and only 3 of 26 reported measurable outcomes beyond 5 years. Quality of life (QOL) was reported by only 3 of the studies; QOL was reported as improved after surgery; however the improvements tended to wane between 6 and 24 months in two of the studies. The review main results were that surgery results in greater weight loss than conventional treatment for obesity defined as a body mass index greater than 30. Reductions in comorbidities, such as diabetes and hypertension, also occur. Improvements in health related quality of life occurred after two years, but effects at ten years are les clear. The Swedish Obesity Study (SOS) is the largest and longest comparison of bariatric surgery and medical management included in the Cochrane review (annotated references 1-4). To the knowledge of the EBM Group, there are no randomized, long-term (Level 1) studies in existence. SOS is a non-randomized, matched cohort (Level 2) study of 2010 obese patients (BMI 34 for men, 38 for women) who had bariatric surgery (376 nonadjustable or adjustable banding, 1369 vertical banded gastroplasty, 265 gastric bypass) and 2037 controls matched on many prognostic factors who were managed conventionally. SOS has reported on changes in pharmaceutical costs up to 6 years post-operatively, disease-oriented outcomes (incidence, rate of recovery from, and prevalence of selected diseases) and quality of life outcomes up to 10 years, and mortality after an average of 10.9 years. Ninety-day post-operative mortality was 0.25% in the surgery group compared to 0.1% mortality in controls. Excluding operations caused by post-operative complications, cumulative re-operation rates were 31% for banding, 21% for gastroplasty and 17% for gastric bypass. Surgery did not result in decreased medication costs (decreased diabetes and cardiovascular medications were offset by increased GI tract, NSAIDs/pain and anemia/vitamin deficiency medications). Rates of recovery from diabetes, hypertriglyceridemia, low levels of HDL-cholesterol, hypertension and hyperuricemia were more favorable in the surgery group than in the control group, whereas recovery from hypercholesterolemia did not differ. Significant improvements in health-related quality of life (HRQL) were positively associated with the amount of weight loss, but about one-third of the

2 surgery group did not have lasting improvements in HRQL because of inability to maintain sufficient weight loss. Surgery was significantly (P=0.04) associated with decreased total mortality: after an average of 10.9 years of follow up total mortality was 101 of 2010 (5.02%) in the surgery group compared to 129 of 2037 (6.33%) in the control group (ARR= 1.31%, NNT=77). For most outcomes, SOS data were insufficient to allow comparisons between different surgical procedures. The impact of more modern medical management might narrow the SOS morbidity and mortality differences, as few SOS patients were on statins as indicated currently. In addition, Procedure-related morbidity and mortality may be greater in community practice than in research settings. Generalizability to the US population is uncertain, as bariatric surgery post-operative morbidity (reference 7) and mortality (reference 8) are higher in the US than reported for SOS. Source: Colquitt J, Picot J, Loverman E, Clegg A J. Surgery for obesity (Review). The Cochrane Database of Systematic Reviews: The Cochrane Collaboration, Picot J, Jones J, Colquitt JL, et al. The clinical effectiveness and cost-effectiveness of bariatric (weight loss) surgery for obesity: a systematic review and economic evaluation. Health Technology Assessment 2009:13(41), DOI: /hta Swedish Obesity Study (SOS): References 1-4 Limitations: Non-randomized (Level 2) study comparing self-selected surgery patients v controls. (1) Sjöström L, Narbro K, Sjöström CD, Karason K, Larsson B, Wedel H, et al. Effects of bariatric surgery on mortality in Swedish obese subjects. New Engl J Med 2007; 357: Findings: Post-operative mortality (up to 90 days) was 0.25% in the surgery group compared to 0.1% in the non-operated control group. Among 1338 subjects who were followed for at least 10 years, the frequencies of re-operations or conversion surgeries (excluding operations caused by postoperative complications) were: banding, 31% (NNH=4); vertical-banded gastroplasty, 21% (NNH=5); and gastric bypass, 17% (NNH=6). After an average of 10.9 years of follow up, total mortality was 101 of 2010 (5.02%) in the surgery group compared to 129 of 2037 (6.33%) in the control group (ARR= 1.31%, NNT=77). For patients without pre-existing coronary disease or stroke, total mortality was 92 of 1964 (4.7%) in the surgery group and 117 of 1988 (5.9%) in the control group (ARR=1.2%, NNT=84). For patients with pre-existing coronary disease or stroke, total mortality was 9 of 46 (19.6%) and 12 of 49 (24.5%), respectively (ARR=4.9%, NNT=21). Comment: At baseline, over 13% of the entire SOS cohort had either diabetes or previous myocardial infarction or stroke but less than 2% of the SOS cohort was treated with a statin. The impact of more modern medical management on the SOS mortality results is unclear, but more intensive medical management that includes statin therapy might decrease the mortality benefit of surgery in current practice. (2) Karlsson J, Taft C, Rydén A, Sjöström L, Sullivan M. Ten-year trends in health-related quality of life after surgical and conventional treatment for severe obesity: the SOS intervention study. International Journal of Obesity 2007; 31: Findings: Health-related quality of life (HRQL) was reported in a subset of 655 of 851 surgically

3 treated and 621 of 852 conventionally treated obese patients. HRQL changes during the 10- year observation period largely followed phases of weight loss, weight regain and weight stability. Improvements and deteriorations in HRQL were associated with the magnitude of weight loss or regain, except for anxiety. Peak improvements in the surgical group were observed during the first year of weight loss, whereas the weight regain phase (mainly between 1- and 6-year follow up) was accompanied by a gradual decline in HRQL. At 10 years, net gains were noted in all HRQL domains compared to baseline. Compared to conventional treatment, surgery was associated with significantly better outcomes for current health perceptions, social interaction, psychosocial functioning and depression; there were no differences for overall mood and anxiety. A maintained weight loss of about 10% was sufficient for positive long-term effects on HRQL, a limit that was achieved in about two-thirds of the surgery group. Difficulties among the third of surgery patients who were unable to control and maintain weight loss is an important topic for further research on optimal management. Comment: Established standards regarding postoperative management following obesity surgery are lacking. These results underscore the importance of exploring long-term, integrated, multi-disciplinary approaches to the medical and surgical management of morbid obesity, that continues many years post-operatively. (3) Sjöström L, Lindroos A-K, Peltonen M, et al. Lifestyle, diabetes, and cardiovascular risk factors 10 years after bariatric surgery. New Engl J Med 2004; 351: Findings: After 10 years weight had increased by 1.6% in controls and decreased by 16.1% in operated patients. The proportion of physically active subjects was higher in the operated group throughout the observation period. At ten years, the rates of recovery (control versus surgery) were 13% versus 36% (NNT=5) for diabetes, 11% versus 19% (NNT=13) for hypertension, 27% versus 48% (NNT=5) for hyperuricemia, and 24% versus 46% (NNT=5) for hypertriglyceridemia. At ten years, new cases (control versus surgery) were 24% versus 7% for diabetes, 28% versus 17% for hyperuricemia, and 27% versus 17% for hypertriglyceridemia (incidences of hypertension were not significantly different). (4) Narbro K, Ågren G, Jonsson E, Näslund I, Sjöström L, Peltonen M. Pharmaceutical costs in obese individuals. Arch Intern Med 2002; 162: Findings: Compared to a non-obese Swedish reference population, at baseline the SOS obese study group (surgery and control combined) took more medications for diabetes, heart disease, NSAIDs/pain, and asthma, suggesting that successful weight loss via bariatric surgery might decrease medication costs. However, this was not the case: after 6 years of follow up, there were no significant differences in overall medication costs between the surgery and control groups (P=.87). At follow up the surgery group had lower costs for diabetes and cardiovascular drugs, but higher costs for GI tract disorders, NSAIDS/pain, and anemia/vitamin deficiency drugs. (5) Buchwald H, Avidor Y, Braunwald E, et al. Bariatric surgery. A systematic review and meta-analysis. JAMA 2004; 292: (Level 2 study) Findings: Mean (95% confidence interval) excess weight loss was 47.5% (40.7%-54.2%) for patients who underwent gastric banding; 61.6% (56.7%-66.5%), gastric bypass; 68.2% (61.5%- 74.8%), gastroplasty; and 70.1% (66.3%-73.9%), biliopancreatic diversion or duodenal switch. Operative mortality ( 30 days) was 0.1% for the purely restrictive procedures, 0.5% for gastric bypass, and 1.1% for biliopancreatic diversion. Diabetes was completely resolved in 76.8% of patients and resolved or improved in 86.0%. Hyperlipidemia improved in 70% or more of patients. Hypertension was resolved in 61.7% of patients and resolved or improved in 78.5%.

4 Obstructive sleep apnea was resolved in 85.7% of patients and was resolved or improved in 83.6% of patients. Limitations: No assessment of study quality; surgical complication rates beyond 30 days, longterm morbidity, quality of life and total mortality were not included. Comment: Lack of quality control resulted in inclusion of many studies that were rejected by Cochrane. (6) Adams TD, Gress RE, Smith SC, Halverson R, Simper SC, Rosamond WD, et al. Longterm mortality after gastric bypass surgery. New Engl J Med 2007; 357: Limitations: Non-randomized, retrospective cohort study (Level 2 Study). Findings: 7925 Roux-en-Y bariatric surgery patients from one Utah center and 7925 selfreported obese (BMI 35) individuals obtained from a Utah drivers license application list were matched for age, gender and BMI. After an average 7.1 years of follow up, 213 (2.7%) surgery group patients and 321 (4.1%) controls had died (P<.001, ARR=1.4%, NNT=74). Causespecific deaths (surgery versus control) were: Cardiovascular 55 (0.69%) v 104 (1.3%) (ARR=0.61%, NNT=164); Diabetic-related 2 (0.025%) v 19 (0.24%) (ARR=0.22%, NNT=466); Deaths not caused by disease (accident, poisoning, suicide & other) 63 (0.79%) v 36 (0.45%) (ARI=0.34%, NNH=295). There was also a difference in cancer mortality 31 (0.39%) v 73 (0.92%) (ARR= 0.53%, NNT=189) that the authors stated was surprising and that will require confirmation. Comment: Potential biases in favor of surgery include: (1) Treatment bias (the surgery group was probably exposed to additional medical treatment as an adjunct to surgical management, whereas the medical management of the controls was not known; (2) Baseline health status of the surgery group (that underwent preoperative screening) was probably better than that of the unscreened control group, that did not undergo any medical evaluation for this study. (7) Zingmond DS, McGory ML, Ko CY. Hospitalization before and after gastric bypass surgery. JAMA 2005; 294: (Level 3 study) Limitations: Retrospective study of administrative data. Findings: In California from 1995 to 2004, 60,077 patients underwent Roux-en-Y gastric bypass (RYGB). The rate of hospitalization in the year following RYGB was more than double the rate in the year preceding RYBG (19.3% v 7.9%). The most common reasons for pre-procedure admission were obesity-related problems and elective operation, whereas the most common reasons for post-procedure admission were complications often thought to be procedure related, such as ventral hernia repair and gastric revision. For subjects followed for the entire 3- year post-operative period (n=24,678), pre-procedure hospitalizations occurred in 8.4% compared to 20.2% (NNH=9, for excess hospitalizations) in the first post-operative year, 18.4% (NNH=10) in the second year and 14.9% (NNH=16) in the third year. Comment: These morbidity data are likely to be a more accurate reflection of actual results in practice than data from research studies. (8) Flum DR, Salem L, Elrod JAB, et al. Early mortality among Medicare beneficiaries undergoing bariatric surgical procedures. JAMA 2005; 294: (Level 2 study) Limitations: Retrospective study of administrative data.

5 Findings: A total of 16,155 fee-for-service Medicare beneficiaries underwent bariatric procedures between Overall 1-year mortality was 4.6% (NNH=22); 7.5% (NNH=14) for men; 3.7% (27) for women; and 11.1% (NNH=9) for those aged 65 years and older. The odds of death at 90 days were 1.6 times higher for patients of surgeons with less than the median surgical volume. Comment: Mortality was higher than previously reported. These findings are likely to be a more accurate reflection of actual results in practice than data from research studies. (9) Flum DR, Dellinger EP. Impact of gastric bypass operation on survival: a populationbased analysis. J Am Coll Surg 2004; 199: (Level 2 study) Limitations: Retrospective study of administrative data; non-operated control group had worse prognostic characteristics (greater age, male gender, more diabetes). Findings: From , 3,328 patients having bariatric surgery were recorded in the Washington State Hospital Reporting System, and were compared to 62,781 non-operated patients with admitting diagnoses that included obesity or morbid obesity (actual weights and clinical data were not recorded). Operated patients were younger, more likely to be female, and less likely to have diabetes than the non-operated comparison group; 30-day mortality in the operated group was 1.9% and was positively associated with surgeon inexperience. Complete data on total mortality at 10 years were not reported; at 15 years follow up, 16.3% of nonoperated patients had died as compared with 11.8% of operated patients, but these data are based on only 8 patients who underwent bariatric surgery. Comment: 30-day post-operative mortality was higher than previously reported and is likely to be a more accurate reflection of actual results in practice than controlled trial data. Regarding total mortality comparisons, there was a very high likelihood of serious bias in favor of the bariatric surgery group. (10) Christou NV, Sampalis JS, Liberman M, et al. Surgery decreases long-term mortality, morbidity, and health care use in morbidly obese patients. Annals of Surgery 2004; 240: (Level 2 study) Limitations: Retrospective study of administrative data; baseline characteristics of the two groups to determine comparability of other prognostic factors were not reported. Findings: 1035 patients who underwent bariatric surgery at McGill University between 1986 and 2002 were compared to 5746 age- and gender-matched controls from the Quebec database with a diagnosis of morbid obesity (actual weights and clinical data were not measured). At five years post-surgery, incidences of cancer, heart disease, endocrine problems, genitourinary problems, infectious diseases, musculoskeletal ailments, nervous system disorders, psychiatric problems, respiratory disease, skin problems, and mortality all favored the bariatric surgery group; digestive disorders were more frequent in the surgery group. Comment: Very high likelihood of bias favoring the surgery group. (11) MacDonald KG, Long SD, Swanson MS, et al. The gastric bypass operation reduces the progression and mortality of non-insulin-dependent diabetes mellitus. J Gastrointest Surg 1997; 1: (Level 2 study) Limitations: Non-randomized comparison; study groups were not comparable in prognostic variables.

6 Findings: This study compared 154 morbidly obese patients with NIDDM who underwent Rouxen-Y surgery between to 78 morbidly obese patients with NIDDM who did not undergo surgery because of personal preferences or inability to pay for the procedure (control group). Follow up was 9 years for the surgical group, compared to 6.2 years for controls; 23.4% of the surgery group, compared to 50% of the control group, were non-white; 32% of the surgery group, compared to 56% of the controls, were on NIDDM pharmacotherapy (oral hypoglcemics or insulin) at the beginning of the study. Follow up glucose levels and decreased pharmacotherapy favored the surgical group. At the end of follow up 14 (9%) surgical patients and 22 (28%) control patients had died. Comment: High likelihood of bias favoring the surgery group (higher SES, possibly less severe NIDDM based on decreased baseline prevalence of pharmacotherapy). Study occurred before the widespread use of disease-modifying agents (aspirin, statins, ACE-Is) that improve morbidity and/or mortality in NIDDM. (12) Livingston EH, Fink AS. Quality of life. Cost and future of bariatric surgery. Arch Surg 2003; 138: Limitations: Short-term; incomplete data; many subjects lost to follow up. Findings: Review of 11 studies of quality of life (QOL) after bariatric surgery, only 2 of which reported quantitative QOL data 36 months postoperatively. One of these two studies (36 month follow up, 77% patients) reported improved employability, happiness, and self-image at the expense of increased smoking. The other study (86 month follow up, %patients not given) reported improved mobility and employability; but the effects decreased with time. Comment: This review is consistent with the Cochrane conclusions regarding the need for longterm (>5 year) studies on QOL following bariatric surgery. (13) Adams TD, Gress RE, Smith SC, et al. Long-term mortality after gastric bypass surgery. New Engl J Med 2007; 357: (Level 2 study) Limitations: Non-randomized retrospective observational study. Findings This retrospective cohort study compared long-term mortality among 9949 patients who had undergone gastric bypass surgery and 9628 severely obese persons who applied for driver s licenses. During a mean follow-up of 7.1 years, adjusted long-term mortality from any cause in the surgery group was 37.6 vs deaths per 10,000 person-years in controls (P<0.001). Cause-specific death rates were significantly lower in the surgery group for coronary artery disease, diabetes and cancer, but were significantly higher in the surgery group for accidents and suicide. Comment: This historical cohort study is consistent with SOS in suggesting overall diseasespecific benefits for bariatric surgery and also in suggesting that there is a subgroup who will have adverse consequences. These data may be helpful to physicians and patients as part of the shared decision-making process. (14) Sjostrom L, Peltonen M, Jacobson P, Sjostrom CD, Karason K, Wedel H, Ahlin S, Anveden A, Bengtsson C, Bergmark G, Bouchard C, Carlsson B, Dahlgren S, Karlsson J, Lindroos AK, Lonroth H, Narbro K, Naslund I, Olbers T, Svensson PA, Carlsson LM. Bariatric surgery and long-term cardiovascular events. JAMA 2012; 307:56-65

7 Limitations: same as studies 1-4. Findings: This most recent report from the SOS cohort found that, compared wit usual care, bariatric surgery was associated with reduced number of cardiovascular deaths (28 (1.4%) of 2010 v 49 (2.4%) of 2037, ARR = 1%, NNT = 100) and lower incidence of first time (fatal or non-fatal) cardiovascular events (199 (9.9%) of 2010 v 234 (11.5%) of 2037, ARR = 2.5%, NNT = 40) in obese adults. Comment: An accompanying editorial (Livingston EH. Inadequacy of BMI as an indicator for bariatric surgery. JAMA 2012; 307:88-9) pointed out that only insulin resistance but not BMI predicted beneficial outcomes, and called for revising bariatric surgery guidelines to include evaluation of individual patient risk for cardiovascular disease outcomes. Originated: 05/14/07 Updated: 11/1/2011 and 10/11/2013