Obesity places a significant burden on patients, increasing their risk of cardiometabolic complications and adverse health outcomes, as well as the healthcare system, with $1.72 trillion in direct and indirect costs attributed to the disease in 2016. That year, the costs of obesity were equivalent to 9.3% of the U.S. gross domestic product and accounted for 47% of the total cost of chronic diseases. With approximately 50% of U.S. adults forecasted to meet obese criteria and 25% classified as severely obese by the end of the decade, the persisting public health crisis demands intensified intervention.

Existing disease classification methods may contribute to the growing obesity epidemic. More reflective of disease pathophysiology and specific complications causing morbidity and mortality, a new medically actionable disease classification system has been proposed for obesity diagnosis. Highlighting the chronic nature of obesity as a disease, the novel classification method was published in a review in The Obesity Society’s journal, Obesity.

Current Obesity Diagnostic Codes

Currently, the diagnosis of obesity is based solely on body mass index (BMI) measures, which convey no information on the impact of excess adiposity on a person’s health. Per the International Classification of Diseases (ICD) diagnostic code, obesity is classified as “obesity due to excess calories,” not reflecting disease pathogenesis. Moreover, this classification contributes to inadequate methods of prevention and treatment as well as a lack of access to evidence-based therapies and the underrepresentation of obesity as a chronic disease.

New Disease Classification Proposal

The newly proposed system would be based on a different diagnostic term – “adiposity-based chronic disease (ABCD)” – reflecting both pathophysiology and the clinical impact of obesity as a chronic disease. As described in the paper, the coding system would include four distinct domains: pathophysiology, body mass index (BMI) classification, specific biomechanical and cardiovascular complications, as well as the degree of complication severity. The final domain will incorporate disease staging, specific complications that impact health, the basis for clinical intervention, individualized treatment goals, and a personalized medicine approach to treatment.

“The coding reflects ‘what we are treating’ and ‘why we are treating it’, and, hopefully, will provide impetus for greater access of patients to evidence-based treatments,” corresponding author W. Timothy Garvey, MD, director of the Diabetes Research Center at the University of Alabama told Medical Dialogues.

Personalized Approach to Obesity

There is increasing recognition across the globe of the inadequacy of BMI measures and other simplified metrics to comprehensively depict the complexity of obesity or patient health status. Experts believe providers may currently be under-diagnosing obesity as a result of the overly simplistic BMI-based diagnostic coding model. As part of a growing initiative to expand the current definition of obesity, both the American Association of Clinical Endocrinologists (AACE) and the European Association for the Study of Obesity (EASO) have adopted the concept of ABCD.

‘It is time for obesity to enter the era of precision medicine, with novel classification systems based on functionally established endpoints,” according to Gema Frühbeck, first author of a recent EASO paper published on ABCD.

Based on a scientifically correct and medically actionable definition of obesity, Dr. Garvey’s advanced classification model will reflect pathophysiology and clinical impact of the condition. The newly proposed changes to the obesity classification system implicate a forthcoming improved standard of care for patients with obesity, as well as more targeted prevention methods – matched to disease severity and aligned with clinical efforts to personalize individual diagnoses and customize treatment strategies. Ultimately, these developments may lead to a greater acknowledgment of ABCD as a chronic disease, improving accessibility to evidence-based therapies for patients and subsequently, their long-term health outcomes.