More proof needed on costly diabetes drugs

By Julie Steenhuysen
CHICAGO , 30 oct 2008– U.S. doctors are using a wider array of newer, more costly drugs to treat diabetes with little long-term proof that they work better than older, cheaper medications, U.S. researchers said on Monday.
They said newer treatments boosted the average cost of a diabetes prescription by nearly 40 percent in six years.
A separate team that combed through clinical trial data found only the drug metformin cut the risk of heart problems in people with type 2 diabetes, the most common form in which the body gradually loses its ability to respond to insulin.
Taken together, the studies make the case for more long-term data on diabetes drugs as Americans' poor diet and rising rates of obesity are expected to swell the number of diabetics to 29 million by 2050, up from 21 million.
"Diabetes is common and costly. More than one in every 10 healthcare dollars goes to treating diabetes or its complications," said Dr. Caleb Alexander of the University of Chicago, whose study appears in Archives of Internal Medicine.
Alexander and colleagues analyzed prescription data from U.S. patients 35 and older with type 2 diabetes who visited a physician's office between 1994 and 2007. Information about medication costs was available from 2001 to 2007.
They found the annual cost of diabetes drugs rose to $12.5 billion in 2007 from $6.7 billion in 2001.
Alexander said more diabetics using more and newer drugs fueled the rise. Yearly patient visits for diabetes rose to 36 million in 2007 from 25 million in 1994, and the average number of drugs per patient rose to 1.63 from 1.14. The average cost per prescription rose to $76 in 2007 from $56 in 2001.
LESS OLD, MORE OF THE NEW
During this time, prescriptions for older and cheaper sulfonylurea drugs fell to 34 percent from 67 percent of treatment visits, while those for drugs such as metformin and glitazones, such as Takeda Pharmaceutical Co Ltd Actos or pioglitazone and GlaxoSmithKline's Avandia or rosiglitazone, increased.
Newer forms of insulin helped drive costs, as did new drugs such as Merck & Co Inc's Januvia or sitagliptin, which made up eight percent of prescriptions in 2007, and Eli Lilly and Co and Amylin Pharmaceuticals Inc's Byetta or exenatide, prescribed four percent of the time in 2007.
"Some of these drugs may represent valuable pharmaceutical innovation, but I think the need for greater evidence regarding their safety and effectiveness is important since they cost eight to 10 times more than some of the older, more time-tested alternatives," Alexander said in a telephone interview.
Elizabeth Selvin of Johns Hopkins in Baltimore and colleagues analyzed data on heart problems in 40 clinical trials of diabetes drugs published on or before January 2006. Twenty seven of the studies lasted less than one year.
Only metformin cut the risk of death or other heart problems. And only Avandia appeared to raise the risk of death or problems such as a heart attack or stroke, but that did not reach statistical significance, the researchers said.
They said poor quality and inconsistent reporting of heart data, along with the lack of long-term studies, make it hard to draw firm conclusions about diabetes medications.