Sarah SmithAt a recent American Medical Association (AMA) meeting, a new policy was adopted concerning the use of body mass index (BMI) in medicine. For decades, BMI has served as an easy to calculate metric for assessing a patient’s health. The AMA report highlighted concerns with the history of the metric and its inability to account for differences in race, gender, age, and more. As a result, the new policy suggests that doctors should be educated about these issues and consider alternatives when diagnosing obesity.
What is BMI?
BMI is an equation used to estimate how much bodyfat someone has based on their height and weight. Theoretically, the lower a person’s BMI, the less body fat they have. Though BMI is linked to body fat when applied to the general population, it isn’t always accurate on an individual basis. The AMA has now recognized that BMI isn’t a perfect measurement, especially since it’s based mainly on data from non-Hispanic white groups from past generations. The context in which this equation was created combined with the overly simple approach it takes to estimating body fat ignore important factors such as muscle and fat distribution across race/ethnic groups, sexes, genders, and age-span.
Here is an example of how inaccurate BMI can be as a measure of body fat. Actor Dwayne Johnson is 6’ 5” and weighs 260 lbs. He is famous for how fit and lean he is for a lot of his roles but his calculated BMI (30.8) suggests he is obese.
Financial Implications
The trouble with using BMI as a health metric extends beyond painting an inaccurate picture of a patient’s health. It could also determine whether patients receive insurance reimbursement for certain treaments. The AMA policy addressed this directly, emphasizing that BMI should not be the only factor when approving or denying insurance reimbursements. They suggest using BMI alongside other health indicators such as measurements of visceral fat, body adiposity index, body composition, relative fat mass, waist circumference, along with certain genetic and metabolic factors.
In a recent statement, the AMA’s Immediate Past President Jack Resneck, Jr. M.D. said “It is important for physicians to understand the benefits and limitations of using BMI in clinical settings to determine the best care for their patients.”
References
- Calculate your body mass index. National Heart, Lung, and Blood Institute. Accessed October 25, 2023. https://www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmicalc.htm
- Heymsfield SB, Peterson CM, Thomas DM, Heo M, Schuna JM Jr. Why are there race/ethnic differences in adult body mass index-adiposity relationships? A quantitative critical review. Obes Rev. 2016;17(3):262-275. doi:10.1111/obr.12358
- Jakubek K. AMA adopts new policy clarifying role of BMI as a measure in medicine. American Medical Association. June 14, 2023. Accessed October 25, 2023. https://www.ama-assn.org/press-center/press-releases/ama-adopts-new-policy-clarifying-role-bmi-measure-medicine
- Vafiadis D. Obesity treatment and medicare: a guide to understanding coverage. National Council on Aging. July 17, 2021. Accessed October 25, 2023. https://www.ncoa.org/article/obesity-treatment-and-medicare-a-guide-to-understanding-coverage
