Medical Terminology for Super Obesity
Class III obesity (BMI ≥40 kg/m²) is the medical term for severe or morbid obesity, while super obesity is defined as BMI ≥50 kg/m², and super-super obesity refers to BMI ≥60 kg/m².
Classification of Obesity by BMI
The American Heart Association and World Health Organization classify obesity based on Body Mass Index (BMI) into the following categories 1, 2:
| Classification | BMI (kg/m²) |
|---|---|
| Underweight | <18.5 |
| Normal weight | 18.5-24.9 |
| Overweight | 25-29.9 |
| Class I obesity (mild) | 30-34.9 |
| Class II obesity (moderate) | 35-39.9 |
| Class III obesity (severe/morbid/extreme) | ≥40 |
| Class IV obesity (super obesity) | ≥50 |
| Class V obesity (super-super obesity) | ≥60 |
Health Implications of Super Obesity
Super obesity carries significantly greater health risks than lower obesity classes:
Mortality impact: Super obesity reduces life expectancy dramatically - white women aged 20-30 with BMI ≥45 kg/m² lose approximately 8 years of life, while men lose approximately 13 years 2
Cardiovascular risk: Extremely high BMI is associated with "extremely high" risk for cardiovascular disease 2
Surgical risk: Super obese patients (BMI ≥50) and super-super obese patients (BMI ≥60) face substantially higher perioperative risks 3
Comorbidities: The risk of developing serious comorbidities rises dramatically with increasing BMI, including:
- Type 2 diabetes
- Hypertension
- Sleep apnea and obesity hypoventilation syndrome
- Cardiac arrhythmias
- Deep vein thrombosis
- Pulmonary embolism
- Heart failure 2
Clinical Significance
The distinction between different classes of extreme obesity is clinically important because:
Treatment approaches differ: Super obese patients often require more aggressive interventions, including consideration of bariatric surgery when BMI exceeds 50 kg/m² 4
Surgical risk stratification: The Obesity Surgery Mortality Risk Score includes BMI ≥50 kg/m² as one of five key risk factors for perioperative mortality 2
Resource allocation: Super obese and super-super obese patients may require specialized equipment, additional personnel, and modified care protocols 3, 5
Important Considerations
BMI has limitations as a diagnostic tool, with low sensitivity (only 36% in men and 49% in women) and does not distinguish between lean and fat mass 1
For more accurate diagnosis of obesity-related health risks, waist circumference should be measured alongside BMI to assess fat distribution 1
In children and adolescents, severe obesity is defined differently: BMI ≥120% of the 95th percentile or an absolute BMI ≥35 kg/m², whichever is lower based on age and sex 2
The terminology for extreme obesity continues to evolve as the prevalence increases, with super obesity (BMI ≥50) and super-super obesity (BMI ≥60) now recognized as distinct clinical entities requiring specialized approaches to care.