Obesity: Definition and Health Risks

Obesity Definition and Causes

• Obesity is a chronic condition resulting from excess body fat.
• Defined primarily by Body Mass Index (BMI).
• BMI is calculated as weight (kg) divided by height (m²)².
• Overweight: BMI 25-30 kg/m²
• Obese: BMI > 30 kg/m².
• Obesity stems from a long-term energy imbalance where calorie intake exceeds expenditure.
• Factors influencing energy balance include metabolism, appetite, diet, and physical activity.
• Genetic factors play a role, but environmental changes (promoting overeating and reducing activity) are the primary driver of the recent rise in obesity.
• Certain medications (e.g., corticosteroids, antipsychotics) and endocrine disorders (e.g., Cushing's, PCOS) can also cause obesity.

Health Risks of Obesity

• Obesity is a significant risk factor for various chronic diseases, including:
  • Hypertension
  • Dyslipidemia
  • Diabetes
  • Cardiovascular disease
  • Sleep apnea
  • Osteoarthritis
  • Depression
  • Social isolation
  • Certain cancers
• Mortality risk is highest in very low BMI (<18.5) and highest BMI (>35) individuals.
• Obese patients experience more hospital admissions, outpatient visits, and higher prescription drug costs than those of normal weight.

Treatment of Obesity

• Treatment guidelines exist for adults.
• Candidates for drug treatment include all adults with BMI > 30 kg/m² and BMI ≥ 27 kg/m² with associated chronic disease.
• Candidates for bariatric surgery include morbidly obese adults (BMI > 40 kg/m²), those with BMI ≥ 35 kg/m² with associated chronic disease

Lifestyle Modification

• Caloric restriction and enhanced physical activity are the primary treatments for overweight and obese individuals.
• Behavioral modifications support better adherence to the lifestyle modifications.
• Frequent patient follow-ups are crucial for obesity treatment success.
• Empathy and appropriate communication strategies are important for both patient and clinician.

Medications for Obesity

• Medications aim to complement lifestyle changes, not replace them.
• Used in conjunction with reduced caloric intake.
• Potential candidates are patients with BMI > 30 or BMI > 27 with comorbidities (like diabetes).

Naltrexone/Bupropion (Contrave)

• Regulates appetite through hypothalamic and mesolimbic effects.
• Multiple side effects exist, including but not limited to: suicidal thoughts, acute opioid withdrawal, elevated heart rate & blood pressure, neuropsychiatric effects, hepatotoxicity, seizures, and hypoglycemia.
• Contraindications exist

Orlistat (Alli/Xenical)

• Inhibits fat absorption by inhibiting lipases.
• Side effects include gastrointestinal distress (often temporary), and may increase risk for kidney stones and fat-soluble vitamin deficiencies.
• Contraindicated in pregnancy, chronic malabsorption, and cholestasis.

Phentermine/topiramate (Qsymia)

• Suppresses appetite and enhances satiety.
• Stimulatory side effects include increased heart rate, which can cause insomnia, paresthesia, constipation, and poor memory.
• Contraindicated in: hyperthyroidism, glaucoma, MAOI use, pregnancy
• Black box warning associated with acute myopia and secondary angle-closure glaucoma (primarily within 1 month of use)

Liraglutide (Saxenda, Victoza)

• A GLP-1 receptor agonist, slowing gastric emptying, decreasing intake, and improving beta cell function.
• Side effects include increased heart rate, headaches, hypoglycemia, and gastrointestinal distress.
• Do not use during pregnancy or breastfeeding, and is associated with potential thyroid cancer in animal studies.

Bariatric Surgery

• Most effective treatment for significant and sustained weight loss in severely obese patients.
• Surgery types include gastric bypass (typically 30% weight loss) and gastric banding (typically 20% weight loss).
• Impacts oral medication absorption; altered formulations or avoidance of extended release are necessary.

Pediatric Obesity

• Screening recommendations exist from the USPSTF.
• Initial treatment is lifestyle modifications, like adults.
• Medication use should be part of intensified lifestyle interventions.
• Bariatric surgery reserved for the most extreme cases.

Pregnancy and Obesity

• Pregravid overweight/obesity is a significant risk factor in pregnancy.
• Increased risk of gestational diabetes & pregnancy-related hypertension.
• Medication avoidance during pregnancy.
• Lifestyle modification is the recommended treatment approach.