Revenue Cycle Insider

Go beyond documentation to help end the stigmatization of your obese patients.

On Oct. 1, 2024, ICD-10-CM introduced a new option to code obesity by class. But why were these codes needed? For example, prior to the release of the new codes, you could capture severe, or morbid, obesity with E66.01 (Morbid (severe) obesity due to excess calories). On the surface, that code seems to overlap with a new code, E66.813 (Obesity, class 3), which you can use when a patient’s body mass index (BMI) is equal to or greater than 40. That seems to cover the same territory as E66.01.

After the codes took effect, coders had a lot of questions about why these new codes were created, when they would be applicable, and how they might have the potential to change perception of obesity. Here are our answers.

Why Did the New Obesity-Designated-by-Class Codes Come About?

The National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP) Division of Nutrition, Physical Activity and Obesity of the Centers for Disease Control and Prevention (CDC) submitted the proposal for these codes to the Centers for Medicare & Medicaid Services (CMS). The proposal resulted in the following new codes:

• E66.811 (Obesity, class 1)
• E66.812 (Obesity, class 2)
• E66.813 (Obesity, class 3)
• E66.89 (Other obesity not elsewhere classified)

The CDC requested the new obesity class codes to allow for more accurate tracking of the disease trends. Obesity in the United States is on the rise not only for adults, but for children as well. “With such a high prevalence of obesity, it becomes very important to be able to categorize the disease accurately and according to the best scientific understanding that we have,” according to Brook Belay from the CDC in a presentation to the ICD-10-CM Coordination & Maintenance Committee in September of 2022.

Obesity designated by class is not a new concept; it is well established within professional communities that work with the disease. Additionally, the CDC’s classification system is applicable to both adults and children:

• Adult class definitions
  • Class 1 obesity: BMI of 30 to 34.99
  • Class 2 obesity: BMI of 35 to 39.99
  • Class 3 obesity: BMI of 40 or greater
• Child class definitions:
  • Class 1 obesity: BMI > 95^th percentile
  • Class 2 obesity: BMI > 120% of the 95^th percentile
  • Class 3 obesity: BMI > 140% of the 95^th percentile

Defining by class cut backs on confusion in terminology. Terms like “extreme” or “moderate” can lead to confusion as they do not have set parameters. The E66.81- codes allow for the capture of the stages of obesity to further define the patient’s condition with greater specificity. With so many potential comorbidities associated with obesity, along with the condition’s implications on surgical procedures and numerous other factors, this level of specificity is vitally important to capture the patient’s condition.

When Will Coders Use These Codes?

Which code to choose for a specific encounter will depend on the provider’s documentation. Though classes of obesity are associated with BMI ranges, the coder will not select a code from E66.81- unless the class of obesity is documented by the provider. If the documentation indicates morbid or severe, you will still select a code from E66.0- per the index. If the patient’s obesity is defined by class, you will select a code from E66.81-. There are no guidelines at this time indicating which code would take precedence if documentation reflected both. However, it will be beneficial to educate your providers on the new codes, so they can document their patient's condition with the highest degree of specificity, per their best medical judgement.

Remember: ICD-10-CM also revised the pediatric BMI codes that went into effect this October. Code Z68.54 (Body mass index [BMI] pediatric, greater than or equal to 95th percentile for age) was revised to (Body mass index [BMI] pediatric, 95th percentile for age to less than 120% of the 95th percentile for age). ICD-10-CM 2025 also added two new pediatric obesity codes as well:

• Z68.55 (Body mass index [BMI] pediatric, 120% of the 95th percentile for age to less than 140% of the 95th percentile for age)
• Z68.56 (Body mass index [BMI] pediatric, greater than or equal to 140% of the 95th percentile for age)

How Will This Classification System Change the Perception of Obesity?

ICD-10-CM introduced the new obesity class codes to represent a greater understanding of obesity in the medical community — that it is not simply a disease of excess calories but a chronic inflammatory adiposity-based disease characterized by the dysregulation of cellular and hormonal processes.

More, the classification of “morbid” and “excess calorie” can lead to stigmatization, as the terminology places the blame for the condition on the patient rather than recognizing the complex nature of the patient’s condition. People suffering from obesity are often subjected to discrimination socially, in the workplace and even in the healthcare setting. Working toward greater utilization of categorizing obesity by stages of severity, rather than designating it to be solely based on caloric consumption per E66.0- will hopefully remove the stigma, leading to greater patient utilization of medical services and better patient outcomes.

Claire Stevenson, COC, CIC, CPC, CPMA, CDEO, Medical Coding Quality Analyst, AAPC