Over the past few decades, the number of patients who are overweight and obese has increased in the United States. An estimated 130 million adults currently are considered to be overweight or obese. The impact of an aging population and a projected increased prevalence of obesity, have health care professionals concerned. However, little information is available on the impact of obesity on long-term health care costs. To remedy this, Daviglus and colleagues examined data from the Chicago Heart Association Detection Project in Industry.

Investigators screened 39,522 patients 18 years and older between November 1967 and January 1973. Information on height, weight, blood pressure, and serum cholesterol levels was collected; a self-administered questionnaire was used to gather demographic data, smoking history, and medical history; and causes of death were obtained over a mean follow-up of 32 years. Medicare claims data also were collected, from which diagnosis-related annual and cumulative charges were calculated.

From the initial study population, after exclusions, two Medicare-eligible cohorts—for whom short-term or cumulative charges were available—were identified. These were grouped according to BMI: nonoverweight (BMI, 18.5 to 24.9 kg per m²); overweight (BMI, 25 to 29.9 kg per m²); obese (BMI, 30.0 to 34.9 kg per m²); and severely obese (BMI, 35 kg per m² or more). Three statistical models were used, each model adjusting for increasing numbers of confounders, (e.g., baseline age and race in model 1, and additionally for education and smoking in model 2) and additional risk factors (e.g., minor baseline electrocardiographic changes in model 3).

More men than women were overweight or obese at baseline. All inpatient and outpatient Medicare charges were higher in overweight and obese men. Women also had graded increases in charges correlated to increased BMI, with only mild attenuation using model3. Analyses consistently showed a positive relationship between BMI and cardiovascular disease and diabetes-related charges.

The authors conclude that being overweight and obese in young adulthood and middle age are associated with increased Medicare costs in later life for men and women. Unlike other studies using statistical projections, this 19-year prospective study was based on an actual cohort. The study used baseline BMI measurements without determining whether the participants’ weight changed over the study period, and researchers looked only at Medicare costs. Actual expenditures related to obesity and its consequences are likely to be higher.