Obese adults in the United States use a number of prescription drug types more frequently than normal-weight adults, says a new study from researchers at the Centers for Disease Control and Prevention.

Medications to treat high blood pressure and High cholesterol topped the list. Roughly a third of obese adults over the age of 20 used at least one drug to lower blood pressure and one in five used a cholesterol-lowering drug. That compares to about 17 percent of normal-weight adults on blood pressure meds and one in 10 on cholesterol drugs.

More than a third of U.S. adults are obese, according to the CDC, putting them at increased risk of several medical conditions, including heart disease, diabetes, stroke and some cancers.

“Given the health risks of obesity, these results aren’t terribly surprising - they put numbers to a trend we already suspected was taking place,” said Dr. G. Caleb Alexander, a general internist at the University of Chicago who was not involved in the study.

Researchers, led by Dr. Brian Kit at the CDC’s National Center for Health Statistics, analyzed prescription medication use among adults in a nationally representative sample of 10,000 Americans.

The team defined obesity as having a body mass index (BMI) of 30 or higher. BMI is a measure of weight relative to height, so for a 5’9’’ tall person, for example, a BMI of 30 is roughly equal to being 35 pounds above normal weight.

When they looked at the use of 10 different drug classes between the years 2005 and 2008, the researchers found higher numbers of obese Americans were taking eight of the 10 medication types.

In addition to blood pressure and cholesterol drugs, medications for treating diabetes, asthma and thyroid problems, as well as antidepressants and painkillers, were taken by a higher proportion of obese people in some or all age groups.

Sex hormones were the only class of drugs used less by obese people, and sedatives were used about equally among weight groups.

The obese participants were also more likely to be on multiple medications at once, although the researchers saw a similar pattern among adults over 65, regardless of weight.

Among all women over 65, more than 90 percent were taking one medication, 66 percent were taking three or more drugs and 39 percent were taking five or more drugs. Men in the same age group had roughly the same usage.

While obesity is one factor that may contribute to a person’s pattern of prescription drug use, the study found that regardless of weight status, prescription medication use is high among all groups, especially older adults, Kit told Reuters Health in an email.

More than 50 percent of normal weight adults over 20 used one or more prescription medications.

Though the researchers examined the magnitude of prescription drug use, they did not evaluate whether medications were being appropriately prescribed and used.

The findings, they write in Annals of Epidemiology, could just reflect doctors following current treatment guidelines for risk factors like high blood pressure and High cholesterol.

Still, all medications come with side effects, and using more than one prescription drug at once only raises the risk of “adverse events,” they warn.

In 2008, approximately 10 percent of health care spending went toward prescription medications, the authors note. And the results of the study suggest that weight is among the factors that contribute to prescription drug use and expenditures.

We now have a better understanding of the types of medications used by obese versus normal weight adults, said Kit.

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SOURCE: Annals of Epidemiology, November 21, 2011

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Brian K. Kit, MD, MPH,
Cynthia L. Ogden, PhD,
Katherine M. Flegal, PhD