Patients who seek treatment for an eating disorder or obesity are hopeful that their health insurance will cover some of the costs. It all comes down to a measure that was invented nearly 200 years ago by a Belgian mathematician to help him define the “average man” using statistics.
Adolphe Quetelet’s 1830s work at this point appealed to insurance companies. They created “ideal weight tables” after the turn of the century. The measurement, now known as body mass index, was used to monitor and screen for obesity in the 1970s and 1980s.
It’s all around us now. Patients are now able to use an equation, which is essentially a ratio between mass and height, to determine their weight. Adults who score between 18.5 to 24.9 are considered to be within a healthy range.
However, critics – and they are numerous these days – claim that it was not intended to be a diagnostic tool for health. “BMI doesn’t come from science or medicine,” Dr. Fatima Stanza, an obesity medicine specialist who is also the equity director for the endocrine section at Massachusetts General Hospital, said.
Experts agreed that BMI is useful for tracking trends in population weight, but it fails to take into account differences between ethnic groups. It can also target overweight and obese people, such as athletes because it doesn’t distinguish between fat and muscle.
BMI is still a common tool for determining who is most at risk from the health effects of excess weight and who can afford expensive treatments. Despite all the debate around BMI, it is clear that overweight and obese people are more at risk of a variety of health problems including diabetes, liver disease, osteoarthritis (high blood pressure), sleep apnea, heart problems, and even death.
In prescribing instructions for weight loss medications, the BMI measurement is often included. The most recent and most effective drugs such as Wegovy are not recommended for patients with a BMI greater than 30. This is the threshold for obesity. Patients who have at least one weight-related medical condition such as diabetes can be prescribed the drug. Patients who do not meet these label requirements can be prescribed medications by doctors, but insurance may not cover all of the costs.
Most insurers, including Medicare, cover certain forms of bariatric surgery to lose weight. However, some may require that patients have a minimum BMI of 35 and other medical conditions such as diabetes or high blood pressure to be eligible.
It can be more difficult with medications. Medicare does not cover prescription weight loss medications, but it will cover obesity screening and behavioral health treatments. Private health plans may differ in how they cover weight loss medication.
Stanford said, “It’s frustrating because everything that we do in obesity medicine depends on these cutoffs.”
Critics claim that BMI can be erroneous on both ends of a scale. It mistakenly labels larger people as unhealthy or people who are less healthy as healthy.
Insurers often use BMI when deciding on coverage for eating disorders. They can also limit treatment to those who are underweight or denied care by their health plans. Serena Nangia is the communications director at Project Heal.
Nangia stated that because of the emphasis on BMI numbers, people are not getting help sooner even if they have a moderate BMI. “If they’re not overweight, they aren’t taken seriously and their behavior is overlooked.”
Stanford stated that she too has had to fight insurance companies over who is eligible for treatment for excess weight based on BMI. This includes some of the more expensive, higher-cost weight loss medications which can run up to $1,500 per month.
Stanford stated that she has seen patients who are doing well with medication but whose BMI drops below a certain threshold. The insurance company then wants them to stop taking the medication. She also challenged those decisions. “Sometimes, I win, and sometimes I lose.”