Sharma, A. M. & Kushner, R. F. A proposed clinical staging system for obesity. Int. J. Obes. (London) 33, 289–295 (2009).

A clinical staging system for obesity proposed by two internists could improve the estimation of health risks associated with excess weight and thus aid clinicians, researchers and policy-makers in their work.

“...the current system is of limited use to predict overall health, functioning and well-being...”

Sharma and Kushner propose a staging system that includes the patient's medical history and relevant clinical symptoms (for example, impaired levels of fasting glucose, sleep apnea and hypertension). The authors define five stages, from stage 0 (obesity without additional risk factors and comorbidities, which should be managed by lifestyle counseling) to stage 4 (obesity with severe related disorders, which necessitates aggressive intervention).

Previously, individuals with obesity were categorized by descriptive, anatomical or etiological classification systems, which have been replaced by the currently used anthropometric staging system. This anthropometric classification, which is recommended by the NIH and the WHO, is based on BMI measurements and defines five categories for adult individuals with excess weight, from overweight (BMI ≥25 kg/m2) to obese class III (BMI ≥40 kg/m2). BMI is usually used together with waist circumference or waist-to-hip ratio, which reflects the amount of abdominal fat and the independent risk factor for morbidity.

Although BMI and waist circumference or waist-to-hip ratio are appropriate surrogate measures of overall adiposity and visceral adiposity that can be used to compare various populations and to follow longitudinal trends, these measurements do not adequately reflect interindividual differences. In addition, the anthropometric classification system does not take into account comorbid conditions, although obesity-related morbidity greatly depends on risk factors other than body weight. Thus, the current system is of limited use to predict overall health, functioning and well-being of an individual with obesity, although these factors are crucial to make adequate management decisions. Sharma and Kushner claim that the above limitations could be overcome with use of their proposed staging system in combination with existing anthropometric measures.