CHICAGO (American Medical Association) -- Compared to nonobese persons, obese patients had higher average health care costs over a one-year period, according to an article in the October 25 issue of The Archives of Internal Medicine, one of the JAMA/Archives journals.

Background information in the article states that in 2000, a National Health and Nutrition Examination Survey showed that 30.9 percent of people aged 20 to 74 years were obese, defined as having a body mass index (BMI) of 30 or greater.

Obesity is a major risk factor for hypertension, high cholesterol, type 2 diabetes mellitus, heart disease, stroke, gallbladder disease, musculoskeletal disorders, and certain cancers. In 1995, the total costs of obesity were estimated to be over $99 billion.

Marsha A. Raebel, Pharm.D., from the Clinical Research Unit, Kaiser Permanente of Colorado, Denver, and colleagues compared the one-year health care costs in 539 obese and 1,225 nonobese people, matched by age (within five years), sex, and primary outpatient medical office.

Age and sex distribution were similar in both groups. The average age of the obese group was 48.2 years, and the average age of the nonobese group was 49.1 years.

The average BMI for obese patients was 37.9, and the average BMI for nonobese patients was 22.4. Both obese and nonobese patients had a median of one chronic disease.

The researchers found that over a one-year period, the median total health care costs were $585.44 for obese patients, and $333.24 for nonobese patients.

This difference was primarily attributed to prescription drug costs. Obese patients' median prescription costs were $357.65, compared to $157.86 for nonobese patients. New and refill drug prescription use was also greater in obese patients, who had a median of 11 prescriptions, while nonobese patients had a median of six prescriptions in the one-year period.

During the study year, obese patients were 3.85 times more likely than nonobese patients to have been hospitalized (4.8 percent vs. 1.47 percent), although both groups had similar lengths of stay (median of 1.86 days v. 1.84 days).

Also, the average age of obese patients who were hospitalized was younger than nonobese patients who were hospitalized (49 v. 56 years). Obese patients had a median of three outpatient visits throughout the year, while the nonobese group had two.

The authors write: "The economic burden of obesity is significant, even over the relatively short-time period of one year. Our study documents the association between health care expenditures and level of obesity using individual-level data, while taking age, sex, and chronic diseases into consideration."

The researchers conclude: "Further study is needed to establish the economic burden of obesity using data from a longer period."