Q&A: Class 3 obesity

Q: We’re working on an auto-population for the outliers of body mass index (BMI), underweight and morbid obesity. We are considering changing our terminology for morbid obesity to class 3 obesity as, now that patients have access to their online records, they may be unhappy with seeing “morbid obesity” used in their charts. According to Coding Clinic, second quarter 2022, p.9, you can “assign code E66.01 Morbid (severe) obesity due to excess calories, for Class 3 obesity.” Do you foresee any issues that could arise when submitting this documentation to payers?

A: First, I want to make sure I understand what you’re asking correctly. I believe you’re working to auto-populate the BMI when specific diagnoses are documented by the provider. If so, documentation of class 3 obesity would allow the BMI to be reported. If you’re asking if you can auto-populate the diagnosis of class 3 obesity for a BMI over 40, however, the answer is no. The provider must document the diagnosis.

The CDC differentiates obesity into three classes:

• Class 1: BMI 30 to <35
• Class 2: BMI of 35 to <40
• Class 3: BMI of 40 or higher (severe)

It is too early to know how payers will react to the use of the term “class 3 obesity.” 

Per the recent Coding Clinic you cited, the documentation of class 3 obesity does allow assignment of E66.01. If you’re challenged by a payer, I would use that Coding Clinic in your defense. You can also back this up with the CDC definition indicating class 3 is a BMI greater than 40. This article from the National Institutes of Health offers a description of Class 3 obesity, and more information is available at this website too. 

I would think there should be no reason for a payer to challenge the documentation of the diagnosis if it is clearly written:

• by the provider
• with a BMI greater than 40
• with documentation as to the significance of the class 3 obesity by linking to any/all comorbidities
• with documentation as to how it is managed and concerns for new or worsening complications if not addressed

Editor’s note: Laurie Prescott, RN, MSN, CCDS, CCDS-O, CDIP, CRC, ACDIS interim director and CDI education director, answered this question. Contact her at lprescott@acdis.org.