AIM: Costlier new diabetes drugs do not necessarily produce better outcomes

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While the annual cost of prescription diabetes drugs nearly doubled to $12.5 billion between 2001 and 2007, questions remain whether the higher cost actually translates into improved care and better outcomes, according to a study in the Oct. 27 issue of Archives of Internal Medicine.

The study's first author, G. Caleb Alexander, MD, assistant professor of medicine at the University of Chicago, pointed out that FDA approval does not require that a drug be compared against alternative treatments; it only has to be safe to use and better than a placebo. Nor, he said, does a company have to demonstrate that a drug's effectiveness justifies its price.

New drugs such as sitagliptin (brand name Januvia, $160 per prescription) and exenatide (Byetta, $210) cost eight to 11 times more than older, generic drugs such as metformin or glipizide.

According to the authors, drug companies market the new drugs with claims of greater convenience and better control of blood sugar levels, and physicians have increasingly used them as alternatives to injected insulin, Alexander said. Insulin use has correspondingly dropped from 38 percent of treatment visits in 1994 to 28 percent in 2007.

However, the new drugs and combinations of drugs do no automatically lead to improved outcomes, said the study’s senior authors Randall Stafford, MD, PhD, associate professor of medicine at the Stanford Prevention Research Center in California. “Just because a drug is new or exploits a new mechanism does not mean that it adds clinically to treating particular diseases. And even if a new drug does have a benefit, it's important to consider whether that benefit is in proportion to the increased cost of new therapies.”

He added that prescribing may need to be more selective, so that the more expensive drugs are used in patients who will truly benefit from them.

There are other reasons for the higher costs, Stafford noted. More people are being diagnosed with diabetes. In 2000, 4 percent of the U.S. population had diabetes; by 2050, the percentage is expected to increase to 7 percent. Lifestyle factors contribute to that increase, according to the authors.

Physicians are also screening for diabetes more intensively and diagnosing patients at milder stages of the disease. In addition, patients are treated more aggressively in keeping with the increasing emphasis on optimal control of blood sugar in diabetes. The study also found that patients are increasingly being prescribed more than one medication. In 1994, 82 percent of patients were prescribed only one drug; in 2007, only 47 percent were.

Regardless, diabetes is becoming more expensive to treat. In 2002, it was associated with more than 10 percent of U.S. healthcare expenditures.

"Although increasing costs of therapy are partly due to more patients with diabetes and more medications per patient, the greatest contributor to increasing costs is the substantially greater use of newer, more costly medications,” the authors concluded.

“We hope our findings will prompt researchers and policymakers to consider the changes in treatment that are taking place and take steps to better evaluate newer treatments,” Alexander said.