Pocket – Obesity

Mar 13, 2020 admin NỘI TIẾT 0

Obesity
Pocket Primary Care, 2018

Background

(NEJM 2017;376:254)

  • Obesity is a multifactorial, chronic disease affected by social, behavioral, cultural, metabolic, & genetic factors
  • Body mass index: (weight [kg]/height [m2]); serves as proxy for amount of relative body fat; however, this is indirect, & ↑ BMI may reflect higher lean mass for certain pts (e.g., athletes)
  • Classification: Obese: BMI ≥30; overweight: BMI >25
  • Comorbidities: Health risks assoc w/ obesity include prediabetes & DM2, HTN, HLD, CVD, gallstones, NAFLD, GERD, OA, cancer, OSA, stroke, mood/anxiety/eating d/o, disability, ↑ mortality (obesity itself accounts for ~5–15% US deaths/y) (NEJM 2009;361:2252)
  • Epidemiology: >1/3 US adults obese, >2/3 overweight or obese; dramatic (>2×) ↑ prevalence in past 30 y, now leveling off (JAMA 2016;315:2284)
  • Risk factors: Assoc w/ ↑ age; race/ethnicity: non-Hispanic black >Mexican-Americans > any Hispanic race/ethnicity; ↓ socioeconomic status; ↓ education (♀ only)

Evaluation

  • Screening: All adults by BMI & waist circumference at periodic health visits
  • History: Complications (as above), RFs for complications (tobacco use, ⊕ FHx CAD); Contributing factors: (Mood d/o, hypothyroidism); Meds: Especially those w/ wt-related s/e (atypical antipsychotics, antidepressants, antiepileptics, diabetes medications, glucocorticoids); Social hx: Support system, resources (time, money), motivations for wt loss, barriers to wt loss; stressful life events
  • Weight history: Past wt loss attempts (incl meds, surgery), diet (esp fast food, sugary beverages, snacks, portion size, timing of eating), physical activity, ⊕ FHx obesity
  • Physical exam: Height, weight, waist circumference, BP; look for signs of insulin resistance (acanthosis nigricans), hypothyroidism, & Cushing syndrome

Visceral abdominal adiposity strongly associated w/ obesity complications: Waist circumference >40″ (♂)/>35″ (♀) independently ↑ health risks in pts w/ BMI <35 (note ↓ cut-offs in people of East Asian descent: >35″ (♂)/ >31″ (♀) (AHRQ 2011; 11- 05159-EF-1)

  • Lab: Chem 7 (Cr for HTN/DM-related renal disease screening), LFTs (NAFLD screening), TFTs (r/o underlying hypothyroidism), HbA1c (DM screening), fasting lipids (HLD screening); consider Vit D (frequently comorbid Vit D deficiency)

Treatment

(Obesity 2014;22(S2):S1)

  • General approach: Goals are (1) prevent further wt gain, (2) reduce body wt, (3) maintain wt loss over long term; gradual wt loss (rate = 1–2 lb/wk) w/ initial goal of 5–10% wt loss recommended
  • Indications for weight loss: Recommended if BMI > 25 kg/m2 or high- risk (waist circumference plus ≥2 CV RFs)
  • Benefits: Health benefits seen w/ any wt loss, even if pt remains above ideal body wt (↓ risk DM, HTN, CVD, HLD, disability; ↓ HbA1c for pts w/ DM)

Lifestyle Modification

  • Comprehensive behavioral change = cornerstone of therapy; may encourage small steps toward change if not ready for lifestyle overhaul; see “Counseling Patients”; set goals/metrics for success to keep motivated
  • Energy balance equation: Net body balance (wt) = Energy input (food) – Energy output (metabolism, physical activity)
  • Diet: Low-calorie diet essential; recommend ∼1200–1500 kcal/d ♀, 1500–1800 kcal/d ♂; reduction of 500 kcal/d results in wt loss of 1 lb/wk; nutritionist can offer more precise calc.
  • Low carbohydrate, low fat, Mediterranean diet, DASH diet, & other diets all effective → patient preference & adherence key factor (NEJM 2009;360:859)
  • Recommend ↓ soda & sugary beverage consumption as appropriate (25% of US consumes >200 kcal/d of soda) (NCHS Data Brief 2011;71:1); reframe as “liquid candy”
  • Recommend ↓ EtOH intake as appropriate (20% of men consume >300 kcal/d of EtOH ≈ 2 beers) (cdc.gov, NHANES 2013)
  • Exercise: Exercise alone may not → significant wt loss (Obesity 2011;19:100), but important for prevention of wt gain & ↓ CV/DM risk independent of wt loss (Arch Int Med 2008;168:2162); AHA recommends ≥150 min/wk moderate to vigorous activity (e.g., 30 min/d 5 d/wk)
  • Weight Self-Monitoring: Encourage weighing at home ≥1×/wk, both for wt loss & wt maintenance
  • Behavioral therapy: offer referral to high-intensity comprehensive lifestyle intervention (14 visits in first 6 mos), where pt will have regular feedback & support from trained healthcare professional, complete behavior change curriculum, & monitor food/exercise/wt
  • Group programs: YMCA diabetes prevention program (AJPH 2015;105:2328) & commercial wt loss programs like Weight Watchers (JGIM 2013;28:12) effective for some patients

Pharmacotherapy

(J Clin Endocrinol Metab 2015;100(2):342)

Indications: Obese or BMI ≥27 w/ CV RFs who have failed lifestyle modifications alone

General considerations: Always prescribe in combination w/ ongoing lifestyle modification counseling (AHRQ 2011; 11–05159-EF-1); titrate ↑ from lowest dose; wt loss effect often lost after medication d/c; newer nongenerics costly & usually not covered by insurance

Orlistat (Xenical, Alli): FDA-approved for chronic wt mgmt

  • Mechanism: Lipase inhibitor → ↓ fat digestion/absorption
  • S/e: Bloating, flatulence, oily stools, ↓ fat-soluble vitamin absorption Contraindications: Pregnancy, chronic malabsorption, gallbladder disease Notes: Less costly ½ strength OTC formulation available (Alli); Rx w/ multivitamin

Phentermine/Topiramate ER (Qsymia): FDA-approved for chronic wt mgmt

  • Mechanism: (P) Inhibits NE/5HT reuptake & (T) enhances GABA activity, glutamate antagonist → ↓ appetite, ↓ food intake S/e: (P) Tachycardia, HTN → monitor BP/HR; (T) teratogenic, cognitive dysfunction, metabolic acidosis, constipation, dysgeusia Contraindications: Pregnancy, hyperthyroidism, MAOI use, glaucoma Notes: Qsymia more effective than phentermine alone (CONQUER, Lancet 2011;377:1341); phentermine alone is generic, FDA-approved for wt mgmt for ≤ 3 mos

Lorcaserin (Belviq): FDA-approved for chronic wt mgmt

  • Mechanism: 5HT 2C receptor agonist → early satiety, ↓ food intake S/e: HA, nausea, fatigue, constipation, hypoglycemia (if DM) Contraindications: Pregnancy, serotonergic drug Rx (SSRI, SNRI)
  • Notes: No effect on 5HT 2B receptor (which in fenfluramine → valvular disease)

Bupropion SR/Naltrexone SR (Contrave): FDA-approved for chronic wt mgmt

  • Mechanism: (B) Inhibits NE/dopamine reuptake & (N) opioid antagonist → ↓ food intake S/e: Tachycardia, HTN → monitor BP/HR; HA, nausea, vomiting, dizziness, insomnia Contraindications: Pregnancy, seizures, uncontrolled HTN, chronic opioid use, MAOI use Notes: Helpful for pts w/ frequent thoughts of food & food cravings

Liraglutide (Saxenda): FDA-approved for chronic wt mgmt

  • Mechanism: GLP-1 agonist → early satiety, ↓ food intake
  • S/e: nausea, vomiting, diarrhea, pancreatitis
  • Contraindications: Pregnancy, hx pancreatitis, hx medullary thyroid cancer or MEN2
  • Notes: Liraglutide FDA-approved for DM (Victoza) w/ lower max dose (1.8 mg/d) vs. max dose 3.0 mg/d for Saxenda

Bariatric Surgery

(Cochrane Database Syst Rev 2014;8:CD003641; NEJM 2007;357:741; Ann Int Med 2005;142:547)

  • Indications: Pts w/ BMI ≥40 or BMI ≥35 w/ related comorbidities (HTN, OA, OSA) who have failed conventional Rx or BMI ≥30 w/ DM Contraindications: Tobacco/nicotine use, Ψ d/o not well treated for 1 y, eating d/o
  • Efficacy: Surgery more effective at ↓ wt & ↓ comorbidities (DM, HLD, HTN, OSA) than medical Rx for pts w/ BMI >30
  • When referring, document prior wt loss attempts, medical necessity, pt comprehension & accountability; refer to experienced ctr → ↓ surgical risk (Can Fam Physician 2010;56:873)
  • Laparoscopic sleeve gastrectomy: Most common procedure (Obes Surg 2013;23:427; asmbs.org); typical wt loss 25–30%; mortality 0.2–0.5%; shorter operative time & decreased malabsorption complications compared to RnY
  • Laparoscopic Roux-en-Y gastric bypass: 2nd most common procedure; Gold standard bariatric surgery → greatest improvement in GERD, type 2 DM, & HTN; typical wt loss 30–50%; mortality 0.5–0.9%; complications include wound infection/dehiscence, stromal stenosis, hernias, gallstones, vitamin deficiencies, dumping syndrome
  • Other procedures: Laparoscopic adjustable gastric banding less commonly performed in the US due to ↓ effectiveness & complications (band slippage/erosion, pouch dilatation); Investigational & uncommon procedures include intragastric balloon, biliopancreatic diversion, duodenojejunal bypass sleeve, & transoral surgical approaches
  • Weight Regain After Bariatric Surgery: Common (≥20% prevalence; Nutrition 2008;24:832); DDx includes dietary nonadherence, fistula, gastric pouch enlargement, anastomosis dilation. Refer to bariatric center for evaluation & consideration of EGD
  • Monitoring After Bariatric Surgery: patients should continue to be monitored for pre-existing comorbid conditions (HTN, HLD, NAFLD, DM), as well as nutritional deficiencies, depression, & complications of malabsorption (e.g., osteoporosis)

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