Bariatric Surgery: What the Generalist Needs to Know Anne Schafer, MD Chief of Endocrinology & Metabolism, SFVAHCS Associate Professor of Medicine and of Epidemiology & Biostatistics, UCSF
Disclosures Research support: ▫ Investigator-initiated research grant from Amgen ▫ Dietary supplements for research studies donated by Bariatric Advantage and Tate & Lyle
Objectives • Describe the effects of bariatric surgery on cardio-metabolic outcomes and mortality • Identify basic eligibility criteria for surgery • Apply recommendations for post-op medical management, monitoring
Case 1 46 y.o. woman w/ severe obesity, type 2 DM, HTN, GERD • Wt increased from 240 to 280 lbs over last 10 years (BMI 40 to 46 kg/m 2 ) • Lost 20 lbs with Weight Watchers then regained 10 lbs • Walks 30 min 3 times/week Weight loss surgery?
Case 2 61 y.o. man with obesity, type 2 diabetes • 423 375 lbs (BMI 54 48 kg/m 2 ) • Roux-en-Y gastric bypass surgery 240 lbs (BMI 31) Insulin discontinued • New low back pain Why did he fracture?
Obesity is an important and growing public health problem • 38% of US adults (Men 35%, women 40%) 1 ▫ Stage 3 obesity (BMI ≥ 40 kg/m 2 ): 7.7% Men 5.5%, women 9.9% • Lifestyle changes usually do not result in clinically meaningful and sustained wt loss ▫ Rarely of the magnitude needed for those with extreme obesity 1 Flegal, JAMA 2016
Wadden, N Engl J Med 2011
Growing demand for bariatric surgery Almost 10-fold increase in operations performed annually in the early 2000s • 25,000 operations in 1998 220,000 in 2009 1 1 Buchwald, Obes Surg 2009
Malabsorptive Restrictive Biliopancreatic Adjustable diversion with gastric band duodenal switch DeMaria, N Engl J Med 2007
Sleeve Roux-en-Y gastrectomy gastric bypass (RYGB) DeMaria, N Engl J Med 2007
Comparative weight loss outcomes Control LAGB VBG RYGB Sjostrom, JAMA 2012
Comparative weight loss outcomes LAGB Sleeve RYGB Maciejewski, JAMA Surg 2016
Type 2 diabetes • Completely resolved in 77%, and resolved or improved in 86% 1 ▫ 84% resolved after RYGB, 48% after gastric banding • Resolution often occurs days after RYGB, even before marked weight loss 2 • Weight-dependent and weight- independent mechanisms 1 Buchwald, JAMA 2004; 2 Rubino, Ann Surg 2004
Why does diabetes improve/resolve? • All procedures: Weight loss ▫ Weight Insulin resistance • RYGB: Additional endocrine effects 1-3 ▫ GLP-1 Insulin secretion • “Incretin effect” ▫ Ghrelin, PYY Hunger, satiety 1 Rubino, Ann Surg 2004; 2 Laferrere, JCEM 2008; 3 Cummings, JCEM 2004
Diabetes RCTs 1. More diabetes remission with RYGB (75%) and BPD (95%) than conventional medical tx (0%) at 2 yrs 1 2. 150 obese pts w/ uncontrolled DM underwent intensive medical therapy +/- RYGB or sleeve gastrectomy 2 ▫ 12% (medical tx alone) vs. 42% (RYGB) vs. 37% (sleeve) had A1c <6.0% at 12 months 1 Mingrone, NEJM 2012; 2 Schauer, NEJM 2012
HbA1c Intensive medical therapy Sleeve gastrectomy Roux-en-Y gastric bypass Intensive medical therapy # DM Meds Sleeve gastrectomy Roux-en-Y gastric bypass Schauer, NEJM 2012
Hypertension • SBP and DBP as early as 1 week post-op 1 ▫ Weight-independent as well as -dependent mechanisms • HTN resolves or improves in 79% 2 • Complete resolution after 3 yrs in 38% of RYGB pts and 17% of LAGB pts 3 1 Ahmed, Obes Surg 2009; 2 Buchwald, JAMA 2004; 3 Courcoulas, JAMA 2013
Dyslipidemia • Hypercholesterolemia improves in 71%, hypertriglyceridemia in 82% 1 • Resolution of dyslipidemia after 3 yrs in 62% of RYGB pts and 27% of LAGB pts 2 1 Buchwald, JAMA 2004; 3 Courcoulas, JAMA 2013
Cardiovascular outcomes: Swedish Obesity Subjects Study Fatal CV Events Total CV Events • CV deaths: adjusted HR 0.47 (0.29-0.76) Sjostrom, JAMA 2012
Cardiovascular outcomes: Swedish Obesity Subjects Study No interaction with Stronger CV effect if high baseline BMI baseline insulin level Sjostrom, JAMA 2012
Mortality: Swedish Obesity Subjects • 29% reduction in risk after 10 years Sjostrom, NEJM 2007
Mortality: Utah gastric bypass study • Covariate-adjusted mortality: 40% lower in surgery group • Death rates for specific causes: • Lower for CVD, diabetes, cancer • CVD: HR 0.50 (95% CI 0.36-0.69) • Higher for suicide/accidents Adams, NEJM 2007
Mortality: Stronger protective effect in patients with diabetes Lent, Diabetes Care 2017
Objectives • Describe the effects of bariatric surgery on cardio-metabolic outcomes and mortality • Identify basic eligibility criteria for surgery • Apply recommendations for post-op medical management, monitoring
Case 1 46 y.o. woman w/ severe obesity, type 2 DM, HTN, GERD • Wt increased from 240 to 280 lbs over last 10 years (BMI 40 to 46 kg/m 2 ) • Lost 20 lbs with Weight Watchers then regained 10 lbs • Walks 30 min 3 times/week Weight loss surgery?
Bariatric surgery: Eligibility criteria Typical criteria: • BMI ≥ 40 kg/m 2 , or BMI ≥ 35 kg/m 2 with an obesity-related co-morbidity • Failure of lifestyle/medical weight control • Absence of psychological or medical contraindications Undertreated psychiatric conditions Low likelihood of adherence to post-op requirements Poor coping strategies, lack of social support Eating disorders
Bariatric surgery: Eligibility criteria Typical criteria: • BMI ≥ 40 kg/m 2 , or BMI ≥ 35 kg/m 2 with an obesity-related co-morbidity • Failure of lifestyle/medical weight control • Absence of psychological or medical contraindications Potential exclusion criteria (varies by practice): • >400 lbs, tobacco or other substance use/abuse, CHF or pulmonary HTN not responsive to medical therapy, O 2 - dependent COPD, cirrhosis
Case 1 46 y.o. woman w/ severe obesity, type 2 DM, HTN, GERD • Wt increased from 240 to 280 lbs over last 10 years (BMI 40 to 46 kg/m 2 ) • Lost 20 lbs with Weight Watchers then regained 10 lbs • Walks 30 min 3 times/week Weight loss surgery?
Objectives • Describe the effects of bariatric surgery on cardio-metabolic outcomes and mortality • Identify basic eligibility criteria for surgery • Apply recommendations for post-op medical management, monitoring
Post-op management: Diabetes • Anticipate potentially abrupt decrease in insulin/oral diabetes med needs • Often, stop sulfonylureas at surgery • Decrease insulin doses • Metformin often continued • Self-monitoring and self-titration
Post-op management • Anti-hypertensive medications • No preemptive D/C of agents • Monitor closely at visits and adjust • Lipid-lowering medications • Many bariatric surgery pts will continue to meet criteria for statin use • Caution about creating expectations that statins will be d/c’ed post-op
Other medication strategies • Oral meds: crush in initial post-op months • Avoid NSAIDs • Caution with meds dosed based on weight ( e.g., levothyroxine) • Caution about potential malabsorption of meds
Potential metabolic and nutritional complications • Weight regain • Gallstones • Micronutrient • Nephrolithiasis deficiencies • Acute gout • Protein deficiency • Bone loss • Dumping syndrome • Hypoglycemia
Micronutrient deficiencies • Vitamin B12 • Calcium, vitamin D • Iron Malabsorption • Thiamine Less food • Folic acid Different food • Vitamin A • Vitamin K; zinc; selenium; copper
Routine supplements • Multivitamin • 1-2 daily (often 1 bariatric-potency chewable) • Vitamin B12 • 350-1000 mcg/day po or 1000 mcg/month IM • Vitamin D • 3000 IU daily • Iron • Menstruating women; take with ascorbic acid • Calcium citrate • 1200-1500 mg elemental Ca daily from diet + Ca citrate supplement (more for BPD/DS) Parrott, Surg Obes Relat Dis 2017
Biochemical monitoring • Pre-op, q 6 months x 2 years, annually • Vitamin B12 • Calcium • Intact PTH • 25(OH) vitamin D • Ferritin • Thiamine • (Folate, vitamin A, zinc, copper) Heber (Endocrine Society), JCEM 2010; Mechanick (AACE/TOS/ASMBS), Surg Obes Relat Dis 2013
Dumping syndrome • Abdominal cramping, nausea, diarrhea, lightheadedness, flushing, tachycardia • Concentrated sweets hyperosmolarity of intestinal contents influx of fluid into intestinal lumen? • Role of gut peptides? • Perhaps 75% of gastric bypass pts • Often transient issue, early post-op period Heber (Endocrine Society), JCEM 2010
Dumping vs Hypoglycemia Dumping syndrome Hypoglycemia Occurs early after eating Occurs 1-3 hours (~30 min) postprandially Develops in early post-op Develops ≥ 1 year post-op period, often resolving over time • Dx of hypoglycemia requires Whipple’s triad • Symptoms • Low glucose concentration • Resolution of sxs with glucose correction Patti, Lancet Diabetes Endocrinol 2016
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