Association between Body Mass Index and Medical Cost Among U.S. Adults in 2022

OBJECTIVES: Obesity is a chronic disease that affects approximately 42% of US adults and is associated with increased medical expenditures. This study, using measured BMI and medical claims information, aims to update estimates of excess medical expenditures associated with BMI categories among commercially insured US adults in 2022.

METHODS: This study utilized IQVIA’s Ambulatory Electronic Medical Records (AEMR) linked with the Pharmetrics Claims database, which includes de-identified information about geographically diverse inpatient and outpatient encounters of 704,864 persons aged 18-64 years in 2022. Two-part models were used to estimate the association between the outcome variables (medical expenditures and out-of-pocket (OOP) expenditures) and BMI categories (reference: healthy weight), controlling for age, sex, and US Census region.

RESULTS: Compared with persons with healthy weight, persons had higher total medical expenditures in the underweight ($1,913; 95% CI: $1,504 to $2,322), overweight ($219; 95% CI: $126 to $323) and obesity categories. At or above a BMI of 30, excess total expenditures continued to increase, associated with an additional cost of $990 (95% CI: $884 to $1,096) for Class 1, $2,001 (95% CI: $1,863 to $2,139) for Class 2, $2,915 (95% CI: $2,717 to $3,112) for Class 3 obesity, and $3,710 (95% CI: $3,449 to $3,971) for BMI≥45 per person on average. The OOP expenditures presented a similar pattern. The OOP expenditures were significantly higher among persons with underweight ($219; 95% CI: $155 to $283) and persons with obesity with costs as high as $409 [95% CI: $371 to $447] for those with BMI≥45, compared to those with healthy weight. However, OOP expenditures were not significantly higher among patients with overweight (vs healthy weight).

CONCLUSIONS: We found a U-shaped curve of medical expenditures by BMI category. Higher medical expenditures were associated with high and low BMI, and were especially high for persons with severe obesity (BMI>35).