Q&A: Capturing BMI as a CC

Q: I know that CMS doesn’t classify morbid obesity as a comorbid complicating condition (CC) as a secondary diagnosis. Can you please explain why? What diagnoses are classified as CCs by CMS in terms of obesity?

A: The diagnosis of morbid or severe obesity alone is not a CC. The addition of the body mass index (BMI) greater than 40 is the CC. The BMI, however, cannot be captured by coding unless there is an accompanying diagnosis which would be the morbid or severe obesity. Both the BMI and the diagnosis would need to be documented to capture the CC.

If the patient’s provider documented the diagnosis of morbid or severe obesity, the BMI can be captured from other sources like nursing documentation per the Official Guidelines for Coding and Reporting.

Section I.B.14 states:

There are a few exceptions when code assignment may be based on medical record documentation from clinicians who are not the patient’s provider (i.e., physician or other qualified healthcare practitioner legally accountable for establishing the patient’s diagnosis). In this context, “clinicians” other than the patient’s provider refer to healthcare professionals permitted, based on regulatory or accreditation requirements or internal hospital policies, to document in a patient’s official medical record. These exceptions include codes for:

• Body Mass Index (BMI)

• Depth of non-pressure chronic ulcers

• Pressure ulcer stage

• Coma scale

• NIH stroke scale (NIHSS)

• Social determinants of health (SDOH)

• Laterality

• Blood alcohol level

This information is typically, or may be, documented by other clinicians involved in the care of the patient (e.g., a dietitian often documents the BMI, a nurse often documents the pressure ulcer stages, and an emergency medical technician often documents the coma scale). However, the associated diagnosis (such as overweight, obesity, acute stroke, pressure ulcer, or a condition classifiable to category F10, Alcohol related disorders) must be documented by the patient’s provider. If there is conflicting medical record documentation, either from the same clinician or different clinicians, the patient’s attending provider should be queried for clarification. The BMI, coma scale, NIHSS, blood alcohol level codes and codes for social determinants of health should only be reported as secondary diagnoses.

CMS does provide a full list of CCs and MCCs which is updated every fiscal year. You can find that list here.

Editor’s note: Kim Conner, BSN, CCDS, CCDS-O, CDI education specialist for ACDIS/HCPro based in Middleton, Massachusetts, answered this question. Contact her at kconner@hcpro.com.