Role of the Gastroenterologist in Managing Obesity

John K DiBaise; Amy E Foxx-Orenstein

Expert Rev Gastroenterol Hepatol. 2013;7(5):439-451.

Impact of Obesity on GI Procedures

The impact of obesity on the development of GI disorders and the subsequent demand for GI procedures deserves careful consideration. GI endoscopic (esophagogastroduodenoscopy, colonoscopy, endoscopic retrograde cholangiopancreatography) and motility (esophageal manometry, ambulatory esophageal pH ± impedance testing) procedures play a role in the diagnosis or management of the GI symptoms and conditions associated with obesity described previously. As a consequence of the impact of obesity on GI disorders, gastroenterologists can expect an increased need for GI procedures for both diagnosis and treatment.^[52] Of course, GI endoscopy also plays a critical role in the bariatric surgery patient including the preoperative, intraoperative and particularly, postoperative management.^[53] Finally, bariatric endotherapy is an emerging area of endoscopy in obesity. These areas will be discussed further in sections to follow.

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Table 1. Classification of obesity.
Weight Classification	BMI (kg/m²)
Underweight	<18.5
Normal weight	18.5–24.9
Overweight	25.0–29.9
*Obesity*
Class I	30.0–34.9
Class II	35.0–39.9
Class III	40.0 and above
Extreme obesity	>40
Super obesity	>50

Table 2. FDA-approved long-term pharmacologic treatments of overweight and obesity ^†.
Year Approved	Medication	Class	Efficacy	Adverse Effects	Comments
1999	Orlistat (Xenical, Alli)	Gastric and pancreatic lipase inhibitor	- Sustained 5–10% total bodyweight loss	- Borborygmi, cramping, flatulence and anal seepage with oily discharge	- Contraindicated in pregnancy, malabsorptive and cholestatic conditions
	120 mg t.i.d. with food	Fat maldigestion	- Benefits in lipids, blood pressure and glycemic control	- Fat-soluble vitamin deficiencies	- Decrease cyclosporine levels
2012	Lorcaserin (Belviq)	Selective 5-HT2C receptor agonist	- Weight loss 5% over 12 months: 47% for lorcaserin versus 23% for placebo	- Nausea, diarrhea, constipation, dry mouth	- Contraindicated in pregnancy and while breastfeeding
	10 mg b.i.d. with or without food	CNS stimulant and anorexiant	- Improved lipids, blood pressure, glycemic control and waist circumference	- Headache, dizziness, fatigue, back pain	- Discontinue if 5% weight loss not achieved by week 12
				- Edema, hypertension elevates prolactin levels	- Monitor for serotonin syndrome
				- Depression
2012	Phentermine-Topiramate (Qsymia)	Sympathomimetic amine and anticonvulsant	- Weight loss 5% over 12 months: 67% for higher dose compared to 17% for placebo	- Increased resting heart rate, teratogenicity	- Contraindicated in pregnancy, glaucoma and hyperthyroidism
	3.75 mg/23 mg	Anorexiant and anticonvulsant	- Improved waist circumference, blood pressure, fasting glucose and lipids	- Constipation, dry mouth, nausea, dyspepsia	- Requires risk evaluation and mitigation strategy
	7.5 mg/46 mg			- Mood instability, insomnia	- Discontinue if 5% weight loss not achieved by week 12
	15 mg/92 mg			- Paresthesia, headache, dizziness, dysgeusia, fatigue, back pain

†In adults with an initial BMI of >30, >27 when accompanied by a weight-related comorbidity such as hypertension, Type 2 diabetes mellitus or dyslipidemia. 5-HT2C: 5-hydroxytryptamine 2C.

Box 1. Gastrointestinal and liver disorders associated with obesity.
Esophagus Gastroesophageal reflux disease Reflux esophagitis Barrett's esophagus Adenocarcinoma Intestine Crohn's disease Symptomatic diverticular disease Complicated diverticular disease Adenomatous polyps Colon adenocarcinoma Gall bladder Gallstones Cancer Pancreas Acute pancreatitis Adenocarcinoma Liver NAFLD Cirrhosis Hepatocellular carcinoma

NAFLD: Nonalcoholic fatty liver diseases.

Box 2. Gastrointestinal signs and symptoms prompting endoscopy after surgery.
Upper gastrointestinal symptoms Abdominal pain Diarrhea Nausea Vomiting Heartburn Dumping Diarrhea Anemia/bleeding Weight regain Excessive weight loss

Box 3. Gastrointestinal complications prompting endoscopy after surgery.
Marginal ulcers Anastomotic leaks, fistulae and strictures Band stenosis, erosion and slippage Bezoars Choledocholithiasis

Box 4. Nutritional complications after bariatric surgery.
Relatively Common Iron deficiency Hypocalcemia Vitamin D deficiency Vitamin B12 deficiency Uncommon Folate deficiency Thiamine deficiency Thiamine deficiency Copper deficiency Zinc deficiency Zinc deficiency Protein deficiency