Obesity is associated with a higher incidence of several diseases such as diabetes, cardiovascular disease, and cancer, and has been identified as a major risk factor in COVID-19. With obesity becoming a common diagnosis, it has become a focus for payer review of claims. Knowing the nuances of reporting obesity and BMI is critical. Medical billing and coding services are available to help physicians ensure that these conditions are reported accurately for appropriate reimbursement.

Obesity is an epidemic and should be taken as seriously as any infectious disease epidemic, said Jeffrey P. Koplan who was director of the Centers for Disease Control and Prevention from 1998 to 2002. “Obesity and overweight are linked to the nation’s number one killer-heart disease – as well as diabetes and other chronic conditions” he said in a 1999 CDC press release. Koplan stressed the need for a national effort to control the epidemic.

However, despite federal public health policies to control the epidemic, obesity rates have been increasing gradually in the US for over the past three decades. Here are some worrying statistics:

  • In February 2020, the Centers for Disease Control and Prevention (CDC) reported that the obesity rate in America touched 42.4% in 2017-2018 – exceeding 40% for the first time, with 9% of Americans categorized as “severely” obese.
  • The CDC’s 2019 Adult Obesity Prevalence Maps reveal that more than 20% of adults in every state in the U.S. is obese.
  • The U.S. Department of Health and Human Services (HHS) National Institute of Health reports that 5.5 percent of men and 9.9 percent of women in the United States are morbidly obese.
  • More than 70 percent of Americans are overweight, obese, or morbidly obese, as defined by the American Heart Association/American College of Cardiology BMI standards.

Obesity and BMI

Basically, being overweight and obesity means having excessive body fat that poses health risk. The typical method to assess obesity is to use body mass index or BMI – a person’s weight in kilograms divided by the square of height in meters. The CDC classifies adult BMI as follows:

  • BMI less than 18.5 as within the underweight range
  • BMI is 18.5 to <25 as normal
  • BMI is 25.0 to <30 as within the overweight range
  • BMI is 30.0 or higher as within the obese range

Obesity may be further categorized as follows:

  • Class 1: BMI of 30 to < 35
  • Class 2: BMI of 35 to < 40
  • Class 3: BMI of 40 or higher, sometimes referred to as as “extreme” or “severe” obesity

The U.S. National Library of Medicine’s MedlinePlus guide defines people who are 100 pounds (lb) (45 kg) or more as “morbidly obese”.

Childhood obesity is a serious concern in the U.S. as it increases the risk of poor health among adolescents and children. According to the CDC, in the U.S., obesity affected 18.5 percent of youth age 2 to 19 in 2016.

Obesity and COVID-19

Since the outbreak of the novel coronavirus pandemic, several studies have highlighted the link between obesity and COVID-19. Compared to normal-weight people, those who are obese are more likely to have chronic conditions such as heart disease, lung disease, and diabetes that are by themselves risk factors for severe COVID-19.

The Winchester Star referenced a Science magazine article that looked into the results of several studies. One study published in Obesity Reviews evaluated the medical histories of nearly 400,000 patients and reported that obese people affected by COVID-19 were “113% more likely than people of healthy weight to land contracted in the hospital, 74% more likely to be admitted to an ICU, and 48% more likely to die.” The largest descriptive study yet of hospitalized U.S. COVID-19 patients by Genentech researchers found that of the 77% of nearly 17,000 patients hospitalized with COVID-19 29% were overweight (29%) and 48% were obese.

Coding Diagnosis of Obesity and BMI

While obesity is a common diagnosis, coders and medical organizations need to know how overweight, obesity, and morbid obesity diagnosis should be abstracted from records and also follow the guidelines on reporting BMI (www.aapc com).

Obesity-related Codes

E66.9 Obesity, general (not otherwise specified)
E66.01 Obesity, extreme or morbid
E66.0 Obesity due to excess calories
E66.01 Morbid (severe) obesity due to excess calories
E66.09 Other obesity due to excess calories
E66.1 Drug-induced obesity
E66.2 Morbid obesity with alveolar hypoventilation
E66.3 Overweight
E66.8 Other obesity

BMI codes

Z68.1, Z68.20, Z68.21, Z68.22, Z68.23, Z68.24, Z68.25, Z68.26, Z68.27, Z68.28,
Z68.29, Z68.30, Z68.31, Z68.32, Z68.33, Z68.34, Z68.35, Z68.36, Z68.37, Z68.38,
Z68.39, Z68.41, Z68.42, Z68.43, Z68.44, Z68.45

Z68.1 Body mass index [BMI] 19.9 or less, adult
Z68.20 Body mass index [BMI] 20.0-20.9, adult
Z68.21 Body mass index [BMI] 21.0-21.9, adult
Z68.39 Body mass index [BMI] 39.0-39.9, adult

Morbid obesity codes:

Z68.41 Morbid adult obesity with BMI 40.0–44.9:
Z68.42 Morbid adult obesity with BMI 45.0–49.9:
Z68.43 Morbid adult obesity with BMI 50.0–59.9
Z68.44 Morbid adult obesity with BMI 60.0–69.9:
Z68.45 Morbid adult obesity with BMI ≥70:

Guidelines for Reporting Obesity and BMI

  • To report BMI codes, they must be accompanied by a weight diagnosis (such as obesity or overweight).
  • BMI codes should only be reported as secondary diagnoses. To assign BMI codes, they must meet the definition of a reportable additional diagnosis.
  • Do not report a diagnosis of overweight unless the documentation further discusses the patient’s overweight condition or a plan of care for it. Coding Clinic (Fourth Quarter 2018) states that “overweight” must meet the conditions for reporting a secondary diagnosis (www.icd10monitor.com). These conditions are:
    • Clinical evaluation; or
    • Therapeutic treatment; or
    • Diagnostic procedures; or
    • Extended the length of hospital stay; or
    • Increased nursing care and/or monitoring
  • BMI may be documented by other clinicians but the associated diagnosis must be documented by the patient’s provider (i.e., physician or other qualified healthcare practitioner who are legally responsible for establishing the patient’s diagnosis).
  • If a patient’s BMI is documented by clinicians other than the patient’s provider (e.g., nurses and dieticians), it can be coded if the physician documents the clinical significance (i.e., morbid obesity).
  • Morbid obesity impacts both quality scores and risk adjustment calculations, but overweight and obese diagnoses do not qualify for Hierarchical Condition Categories (HCCs) that impact payment.
  • Report BMI measurements for quality reporting purposes using the correct HCPCS Level II codes.
  • Do not report BMI codes during pregnancy.
  • Coders and billers cannot infer obesity from a BMI value.
  • On inpatient claims, code the attending physician’s weight diagnosis.

Reporting overweight, obesity, and morbid obesity diagnosis correctly is critical to avoid auditor scrutiny and maximize reimbursement. Coding specialists in reliable medical billing and coding companies can help physicians ensure that the diagnostic coding is based on the clinical documentation of the condition and associated BMI.