Bariatric Surgery: What the Generalist Needs to Know Anne Schafer, - - PowerPoint PPT Presentation

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/m2)

• Lost 20 lbs with Weight Watchers then

regained 10 lbs

• Walks 30 min 3 times/week

Weight loss surgery?

61 y.o. man with obesity, type 2 diabetes

• 423375 lbs (BMI 5448 kg/m2)
• Roux-en-Y gastric bypass surgery

 240 lbs (BMI 31)  Insulin discontinued

• New low back pain

Why did he fracture?

Case 2

• 38% of US adults (Men 35%, women 40%)1

▫ Stage 3 obesity (BMI ≥40 kg/m2): 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

1Flegal, JAMA 2016

Obesity is an important and growing public health problem

Wadden, N Engl J Med 2011

Almost 10-fold increase in operations performed annually in the early 2000s

• 25,000 operations in 1998 

220,000 in 20091

1Buchwald, Obes Surg 2009

Growing demand for bariatric surgery

DeMaria, N Engl J Med 2007 Biliopancreatic diversion with duodenal switch Adjustable gastric band

Malabsorptive Restrictive

DeMaria, N Engl J Med 2007 Roux-en-Y gastric bypass (RYGB) Sleeve gastrectomy

Sjostrom, JAMA 2012

Comparative weight loss outcomes

Control LAGB VBG RYGB

Maciejewski, JAMA Surg 2016

Comparative weight loss outcomes

LAGB Sleeve RYGB

• 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 loss2

• Weight-dependent and weight-

independent mechanisms

1Buchwald, JAMA 2004; 2Rubino, Ann Surg 2004

Type 2 diabetes

• All procedures: Weight loss

▫  Weight   Insulin resistance

• RYGB: Additional endocrine effects1-3

▫  GLP-1   Insulin secretion

• “Incretin effect”

▫  Ghrelin,  PYY  Hunger,  satiety

1Rubino, Ann Surg 2004; 2Laferrere, JCEM 2008; 3Cummings, JCEM 2004

Why does diabetes improve/resolve?

• 1. More diabetes remission with RYGB

(75%) and BPD (95%) than conventional medical tx (0%) at 2 yrs1

• 2. 150 obese pts w/ uncontrolled DM

underwent intensive medical therapy +/- RYGB or sleeve gastrectomy2

▫ 12% (medical tx alone) vs. 42% (RYGB) vs. 37% (sleeve) had A1c <6.0% at 12 months

1Mingrone, NEJM 2012; 2Schauer, NEJM 2012

Diabetes RCTs

Schauer, NEJM 2012

Intensive medical therapy Sleeve gastrectomy Roux-en-Y gastric bypass Intensive medical therapy Sleeve gastrectomy Roux-en-Y gastric bypass

HbA1c # DM Meds

• SBP and DBP  as early as 1 week

post-op1

▫ Weight-independent as well as -dependent mechanisms

• HTN resolves or improves in 79%2
• Complete resolution after 3 yrs in 38%
• f RYGB pts and 17% of LAGB pts3

1Ahmed, Obes Surg 2009; 2Buchwald, JAMA 2004; 3Courcoulas, JAMA 2013

Hypertension

• Hypercholesterolemia improves in

71%, hypertriglyceridemia in 82%1

• Resolution of dyslipidemia after 3 yrs

in 62% of RYGB pts and 27% of LAGB pts2

1Buchwald, JAMA 2004; 3Courcoulas, JAMA 2013

Dyslipidemia

Sjostrom, JAMA 2012

• CV deaths: adjusted HR 0.47 (0.29-0.76)

Cardiovascular outcomes: Swedish Obesity Subjects Study

Fatal CV Events Total CV Events

Sjostrom, JAMA 2012

Cardiovascular outcomes: Swedish Obesity Subjects Study

No interaction with baseline BMI Stronger CV effect if high baseline insulin level

• 29% reduction in risk after 10 years

Sjostrom, NEJM 2007

Mortality: Swedish Obesity Subjects

Adams, 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

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/m2)

• Lost 20 lbs with Weight Watchers then

regained 10 lbs

• Walks 30 min 3 times/week

Weight loss surgery?

Typical criteria:

• BMI ≥40 kg/m2, or BMI ≥35 kg/m2 with an
• besity-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/m2, or BMI ≥35 kg/m2 with an
• besity-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, O2- dependent COPD, cirrhosis

Bariatric surgery: Eligibility criteria

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/m2)

• 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

• 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: Diabetes

• 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

Post-op management

• 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

Other medication strategies

• Weight regain
• Micronutrient

deficiencies

• Protein deficiency
• Dumping syndrome
• Gallstones
• Nephrolithiasis
• Acute gout
• Bone loss
• Hypoglycemia

Potential metabolic and nutritional complications

• Vitamin B12
• Calcium, vitamin D
• Iron
• Thiamine
• Folic acid
• Vitamin A
• Vitamin K; zinc; selenium; copper

Malabsorption Less food Different food

Micronutrient deficiencies

• 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)

Routine supplements

Parrott, Surg Obes Relat Dis 2017

• 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)

Biochemical monitoring

Heber (Endocrine Society), JCEM 2010; Mechanick (AACE/TOS/ASMBS), Surg Obes Relat Dis 2013

• 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

Dumping syndrome

Heber (Endocrine Society), JCEM 2010

• Dx of hypoglycemia requires Whipple’s triad
• Symptoms
• Low glucose concentration
• Resolution of sxs with glucose correction

Dumping vs Hypoglycemia

Dumping syndrome Hypoglycemia

Occurs early after eating (~30 min) Occurs 1-3 hours postprandially Develops in early post-op period, often resolving over time Develops ≥1 year post-op

Patti, Lancet Diabetes Endocrinol 2016

Hypoglycemia: Potential mechanisms

• Overtreatment with insulin, sulfonylurea
•  Postprandial insulin secretion

▫  Intestinal delivery  rapid  glucose

▫  Incretin effect (GLP-1, GIP)

▫  Islet cell mass

• Non-insulin dependent mechanisms

▫ Dysregulated enteroendocrine secretion ▫ Altered gut microbiota

▫  Bile acids

Patti, Lancet Diabetes Endocrinol 2016

 simple carbs; acarbose

• ctreotide

diazoxide; CCBs X

• Protein deficiency
• Eat protein first; 60-120 g/d or 1.5 g/kg IBW
• Gallstones
• Ursodiol, or simultaneous cholecystectomy
• Nephrolithiasis
• Hydration; low oxalate diet; oral Ca; KCit
• Acute gout
• Prophylactic therapy in appropriate pts
• Bone loss and fracture
• Ca and vit D; consider DXA in at-risk pts

Other prevention, treatment

Heber (Endocrine Society), JCEM 2010; Mechanick (AACE/TOS/ASMBS), Surg Obes Relat Dis 2013

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

1Compston, Gastroenterology 1984; 2Fish, J Surg Res 2010; 3Dixon, Obesity 2007

• Gastric bypass induces abnormalities in

bone metabolism

▫ Early and sustained s in bone turnover ▫ Decreases in bone mineral density (BMD)

• Fewer data for other procedures

▫ Biliopancreatic diversion: similar1 ▫ Gastric band: less impact on bone2,3

Bariatric surgery and skeletal health

BMD decreases substantially

• 18
• 16
• 14
• 12
• 10
• 8
• 6
• 4
• 2

2

6 12 Month % Change from baseline Femoral Neck (DXA)

* *

6 12 Month % Change from baseline Spine (QCT)

• 18
• 16
• 14
• 12
• 10
• 8
• 6
• 4
• 2

2

* *

Schafer, J Bone Miner Res 2015

Bone loss: Potential mechanisms

• Decreased loading
• Nutritional factors

▫  vitamin D and Ca intake ▫  Ca absorption1,2

• Changes in fat-secreted hormones

▫  estradiol ▫  adiponectin

• Loss of muscle mass

1Cifuentes, Am J Clin Nutr 2004; 2Shapses, Am J Clin Nutr 2013

DRAMATIC! RAPID! ^ + MALABSORPTION + RYGB-SPECIFIC NEUROHORMONAL EFFECTS

Intestinal Ca absorption capacity decreases precipitously

Schafer, J Bone Miner Res 2015

Concern for early fracture-related morbidity and mortality among bariatric surgery patients

61 y.o. man with obesity, type 2 diabetes

• 423375 lbs (BMI 5448 kg/m2)
• Roux-en-Y gastric bypass surgery

 240 lbs (BMI 31)  Insulin discontinued

• New low back pain

Why did he fracture?

Case 2

• Not taking Ca or vitamin D supplements
• DXA: Total hip T-score -1.8

Ca (8.5-10.5) Alb (3.3-5.2) Phos (2.5-4.5) Cr (0.6-1.3) 25OH D (30-50) PTH (12-65) 24h Uca (100-250)

8.4 3.6 2.5 1.1 17

• Vitamin D repletion course, daily Ca

carbonate and vitamin D maintenance

8.5 3.5 3.0 1.1 28 80 58

• Increased Ca intake and switched to citrate

8.4 3.7 2.8 1.3 34 144

Recommendations for bone health

Check and replete 25(OH)D pre-op Universal post-op supplements

• Multivitamin, calcium (dose?), vitamin D

Labs q 6 mo x 2 yrs then annually Post-op exercise/resistance training? Monitor BMD by DXA? Pharmacologic therapy for high risk pts?

Heber (Endocrine Society), JCEM 2010; Mechanick (AACE/TOS/ASMBS), Surg Obes Relat Dis 2013

Thank you!