Morbid obesity is a chronic disease in which a person has a body mass index (BMI) of 40 or ≥35 and experiencing obesity-related health conditions.
A BMI is a screening tool that measures the ration of height to weight. Healthcare providers use a BMI, along with other tools, to determine a patient’s health status and risks. Below are the BMI ranges that classify weight.
| Weight Category | BMI |
| Underweight | ≤18.5 |
| Healthy Weight | 18.5 – 24.9 |
| Overweight | 25 – 29.9 |
| Obese (Class I) | 30 – 34.9 |
| Severely Obese (Class II) | 35 – 39.9 |
| Morbidly Obese (Class III) | ≥40 |
Often, a BMI may be abnormal in a healthy patient due to bone or muscle mass. It is the provider’s responsibility to interpret the BMI and provide a clinical diagnosis for each patient.
According to the American Society for Metabolic and Bariatric Surgery, patients who have a BMI ≥ 35 with the following listed comorbid conditions may be clinically diagnosed with morbid obesity and qualify for bariatric surgery.
• Type II Diabetes Mellitus
• Hypertension
• Sleep Apnea
• Non-alcoholic Fatty Liver
• Osteoarthritis
• Hyperlipidemia
• Gastrointestinal Disorders
• Heart Disease
The American Hospital Association indicates that individuals who are overweight, obese, or morbidly obese are at an increased risk for certain medical conditions. These conditions are always clinically significant and reportable when documented by the provider.
Documentation & Coding
The diagnosis of morbid obesity must be made by the provider based on the patient’s condition, clinical criteria, and professional judgment. Morbid obesity cannot be assumed based on BMI alone. The diagnosis is dependent on the provider’s documentation.
Document all comorbid conditions and complications that are impacting medical decision- making along with a detailed assessment, prognosis, and treatment plan for each encounter.
For patients who have had bariatric surgery and/or weight loss, ensure the diagnosis is not being “carried over” and would not be better classified as having a history of morbid obesity rather than morbid obesity as a current condition.
Documentation of a BMI alone cannot be coded unless the associated weight condition is also documented, such as overweight, obesity, or morbidly obese. BMI codes are only used as secondary codes.
| Description | ICD-10 |
| Morbid (severe) Obesity | E66.01 |
| Drug-induced Obesity | E66.1 |
| Obesity Hypoventilation Syndrome | E66.2 |
| Overweight | E66.3 |
| Obesity | E66.9 |
| BMI ≤ 19.9 | Z68.1 |
| BMI 20 | Z68.2- |
| BMI 30 | Z68.3- |
| BMI 40 – 44.9 | Z68.41 |
| BMI 45 – 49.9 | Z68.42 |
| BMI 50 – 59.9 | Z68.43 |
| BMI 60 – 69.9 | Z68.44 |
| BMI ≥ 70 | Z68.45 |
**A dash (-) indicates an incomplete code**
RESOURCES:
AHA coding clinic Q4, 2018, pg. 77
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