Obesity: Approach to Management In Adults

Definitions

  • WHO: “Excess or abnormal fat accumulation that presents a risk to health”
  • CDC: “Weight that is considered higher than what is considered healthy for a given height is described as overweight or obesity”
  • Obesity Medicine Association (OMA): “A chronic, relapsing, multi-factorial, neurobehavioral disease, wherein an increase in body fat promotes adipose tissue dysfunction and abnormal fat mass physical forces, resulting in adverse metabolic, biomechanical, and psychosocial health consequences.”

The American Medical Association (AMA) officially recognized obesity as a chronic disease in 2013.

Screening

Who should we screen?

  • EVERYBODY!!!
    • The USPSTF recommends that clinicians offer or refer adults with a body mass index (BMI) of 30 or higher (calculated as weight in kilograms divided by height in meters squared) to intensive, multicomponent behavioral interventions. [Grade B]

What do we use for initial screening?

  • BMI and (maybe) waist circumference
    • BMI (kg/m2) classifications are based upon risk of CVD for White, Hispanic, and Black individuals:
      • Underweight: BMI < 18.5
      • Normal weight: 18.5-24.9
      • Overweight: 25-29.9
      • Obesity: ≥30
        • Class I: 30.0-34.9
        • Class II: 35.0-39.9
        • Class III: ≥40 (also referred to as severe, extreme, or massive obesity)
    • Waist circumference ≥40 inches (≥102 cm) for males and ≥35 inches (≥88 cm) for females is considered elevated and indicative of increased cardiometabolic risk

BMI: Pros & Cons

  • Pros:
    • BMI and waist circumference are inexpensive and widely available measures
    • BMI correlates to more direct measures of body fat
    • BMI correlates with future morbidity and mortality
  • Cons:
    • The data was initially drawn from actuarial data among white people from the 1930s
    • It was designed to look at a pattern of deaths among a large population, and not to evaluate any one person’s size or health
    • BMI measures “excess” weight rather than excess fat
    • Does not factor in age, sex, ethnicity, and muscle mass which can affect body fat
  • Note: CDC states because BMI does not measure body fat directly, it should not be used as a diagnostic tool. Instead, BMI should be used as a measure to track weight status in populations and as a screening tool to identify potential weight problems in individuals

What else should we be evaluating?

  • Morbidity & Mortality risk, assessed through
    • BMI classification
    • Waist circumference
    • Age of onset of weight gain / obesity 
    • Presence of comorbidities
      • CVD risk factors: HTN, dyslipidemia, elevated TG, DM or impaired fasting glucose, OSA, and cigarette smoking
      • Other comorbidities that interact with obesity: OA, cholelithiasis, NAFLD, PCOS, mental health conditions, physical disability
  • Etiologies, including
    • Genetics
    • Lifestyle contributors (i.e., nutrition, physical activity, sleep)
    • Demographics: SES, environment
    • Trends in weight across the lifespan
    • Medications associated with weight gain
    • Medical conditions associated with weight gain (e.g., hypothyroidism, Cushing’s syndrome, hypothalamic dysfunction, growth hormone deficiency)
  • Appropriate treatment(s)

Why risk stratify with BMI?

Low and elevated BMI is associated with increases in mortality and chronic conditions including T2DM, HTN, dyslipidemia, and CAD.

All-cause mortality versus BMI for each sex in the range 15-50 kg/m2 (excluding the first 5 years of follow-up)
Source: Prospective Studies Collaboration, Whitlock et al. Body-mass index and cause-specific mortality in 900 000 adults: collaborative analyses of 57 prospective studies. Lancet. 2009

The 5 A’s: A Practical Approach to Screening

  • Ask for permission to discuss weight and explore readiness for change, as this is essential for success; then use motivational interviewing to move patients along the stages of change.
  • Assess for obesity and its related health risks; for the potential causes and risk factors of obesity; and for nutrition, physical activity, psychosocial, economic, and environmental factors.
  • Advise the patient on obesity and its associated health risks that can be improved with good lifestyle habits, with or without weight loss; discuss improving health and well-being, not just looking at the scale; and discuss treatment options. • Agree on realistic, modest, and achievable weightloss goals to help maintain motivation, and agree on reducing negative lifestyle behaviour and promoting positive behaviour.
  • Assist patients to overcome identified barriers to weight management, provide self-help materials and resources, help patients identify strategies to improve adherence, and reward specific behaviour to increase motivation (not with food).
  • Arrange follow-up with treating physicians and other health care providers when necessary. Considering the chronic nature of obesity, long-term follow-up is essential. Negotiate and agree on follow-up with the patient, as this is essential for success.

Weight Stigma

Weight stigma is everywhere, including healthcare settings, which we previously discussed in detail in another blog post.

What we can do as clinicians to decrease weight stigma:

  • Recognize that standard medical advice for weight loss (“eat less, exercise more”) perpetuates stigmatization
  • Incorporate the principles of Health at Every Size
  • Use weight-neutral language
  • Respect patients’ healthcare priorities by treating the problem at hand and avoid offering unsolicited weight loss advice
  • Provide the most appropriate equipment for each patient without commenting on it (e.g., BP cuffs, scales, gowns, etc.)
  • Ask yourself if your healthcare setting accommodates people of all sizes (e.g., armless chairs, appropriate exam tables, etc.)

Lifestyle Modifications

Strategies for lifestyle modifications should include a combination of intensive education and support around 3 tenets:

  1. Food choices: Reduce energy intake and consider individual patient preferences
  2. Physical activity / decrease inactive time: Best for weight loss maintenance
  3. Behavior modification: Facilitates strategies to improve self-monitoring and adherence to new food choices and physical activity

Studies establishing the lifestyle intervention protocol:

A closer look at DPP:

  • Purpose: DPP looked at whether lifestyle Intervention and/or taking metformin would delay or prevent T2DM
  • Basic Format: 1-on-1 as well as group sessions over 24 weeks. Visits then liberalized over time
  • Process Results:
    • 92.5% had attended a scheduled visit within the last 5 months of the study
    • 50% in the lifestyle-intervention group had achieved the weight loss goal of 7% or more by the end of the curriculum
    • 74% met the goal of at least 150 minutes of physical activity per week
    • 70% maintained adherence to metformin

A closer look at Look AHEAD:

  • Pros: Improved BP levels, blood glucose levels, blood cholesterol levels, fitness levels, mobility, quality of life, medication use, health care costs, sleep apnea, urinary incontinence, hospitalization frequency
  • Cons:
    • No reduction in CVD event in patients with overweight/obesity and T2DM
    • Risk 30% HIGHER risk in AA group (technically not significantly different)

Pharmacologic Therapy

A number of options are available, which are outlined in the AGA’s 2022 Clinical Practice Guideline on Pharmacological Interventions for Adults With Obesity. Remember that it is always important to first clarify the patient’s goals (e.g., improve health status, sustained weight loss, minimize adverse effects, etc.) prior to initiating an intervention.

Source: Grunvald et al; AGA Clinical Guidelines Committee. AGA Clinical Practice Guideline on Pharmacological Interventions for Adults With Obesity. Gastroenterology. 2022

GLP-1 Receptor Agonists

  • Rx: Semaglutide, Liraglutide
  • MOA: Stimulate glucose-dependent insulin secretion, inhibit glucagon release and gastric emptying
  • Shown to reduce MACEs in T2DM, CVD, and CKD
  • Common side effect is GI upset (N/V/D)
  • Contraindications include pregnancy (semaglutide), h/o pancreatitis, FHx of medullary thyroid cancer or MEN 2A/2B
Source: Müller et al. Anti-obesity drug discovery: advances and challenges. Nat Rev Drug Discov. 2022

Sympathomimetics

  • Rx: Phentermine, diethylpropion, benzphetamine, phendimetrazine
  • MOA: Stimulate NE release and inhibit reuptake, leading to early satiety
  • Side effects include tachycardia, elevated BP, insomnia, dry mouth, constipation, nervousness
  • Only FDA approved for use up to 12 weeks due to concern about misuse potential and side effects (schedule IV controlled substance)
  • Contraindicated in pregnancy/breastfeeding, prior substance use disorder, CVD, HTN, glaucoma, hyperthyroidism, and concurrent MAOi use

Phentermine-Topiramate

  • MOA: Stimulant medication + anticonvulsant that commonly has weight loss as side effect
  • FDA approved for long-term use
  • Potential candidate if GLP-1 receptor agonist failure or contraindicated
  • Same side effects as pure sympathomimetics in addition to potential cognitive disturbances/anxiety/depression
  • Same contraindications as pure sympathomimetics (use with significant caution in patients able to get pregnant)

Buproprion-Naltrexone

  • MOA: Combination dopamine-reuptake inhibitor and opioid receptor antagonist thought to stimulate pro-opiomelanocortin neurons which decrease food intake and regulate metabolism
  • May be beneficials to concurrent smokers or patient’s with AUD
  • Side effects include nausea, HA, constipation
    • Possible risk of increase suicidality in adolescents/young adults early in initiation
  • Contraindications include pregnancy, uncontrolled HTN, seizure disorder, and chronic opioid use

Orlistat

  • MOA: Inhibits pancreatic lipase activity, decreasing fat digestion, increasing fecal fat excretion
  • Less effective than GLP-1 agonists or phentermine-topiramate
  • Improves BP control and decreases LDL and total cholesterol
  • Side effects include lower GI symptoms (borborygmus, oily stools, flatus, cramping), decreased absorption of fat-soluble vitamins, and renal impairment (calcium oxalate stone formation)
  • Contraindicated in pregnancy, h/o malabsorption syndromes, and h/o calcium oxalate stone formation

Drug therapies NOT recommended

  • Locaserin
    • Serotonin receptor agonist
    • Asked by FDA to be removed from the U.S. Market in 2020 due to association with multiple different kinds of cancer
  • OTC Dietary Supplements
    • Not regulated by the FDA
    • Have been found to contain furosemide, fluoxetine, sibutramine, phenytoin
  • Human chorionic gonadotropin
    • Not shown to cause significant weight loss more than placebo

Bariatric Surgery

Bariatric surgical procedures affect weight loss through 3 fundamental mechanisms:

  1. Volume Restriction
  2. Nutrient Malabsorption
  3. The neurohormonal regulation of hunger and energy balance

Indications:

  • BMI ≥40 kg/m2 with or without comorbid illness
  • BMI of 35.0 to 39.9 with at least one serious comorbidity (e.g., T2DM, HTN)
  • BMI between 30.0 to 34.9 with either difficult-to-control T2DM or metabolic syndrome
  • Note: For patients with Southeast Asian heritage, the BMI criteria can be lowered by 2.5 per class, related to a higher prevalence of truncal obesity (i.e., visceral fat)

Weight Loss: Bariatric Surgery vs Pharmacotherapy

With lifestyle measures alone, a weight loss of 5-7 % of body weight is possible but may be difficult to maintain long term.

A weight loss goal of >30% is difficult to achieve and maintain without bariatric surgery.

Source: Müller et al. Anti-obesity drug discovery: advances and challenges. Nat Rev Drug Discov. 2022

Take-Home Points!

  • BMI (+/- waist circumference) is a flawed health metric but not without utility
  • Obesity is a chronic disease impacted by many factors far beyond lifestyle
  • GLP-1 agonists should be considered as first-line medical therapy
  • Bariatric surgery can lead to significant weight loss and should be discussed in the setting of lifestyle/medication failure
  • Access matters and the best treatment plan is the one a patient can do and afford

Blog post based on Med-Peds Forum talk by Ruth Cadet, PGY3, and Fritz Siegert, PGY4