The annual cost for drugs to treat type 2 diabetes nearly doubled between 2001 and 20, skyrocketing from $6.7 billion in 2001 to $12.5 billion six years later, according to researchers from Stanford University and the University of Chicago.

The increased expense, they say, is due to the introduction of new drugs such as Januvia (sitagliptin) and Byetta (exenatide), which can cost eight to 11 times more per dose than traditional drugs such as metformin or a sulfonylurea.

Also contributing to the increase in expenditures is the fact that more type 2 patients are now taking two or more drugs to treat their illness. The researchers noted that in 1994, 82 percent of diabetes patients took only one drug for their condition. By 2007, however, that figure had dropped to 47 percent. 

The researchers also noted that insulin usage among type 2 patients dropped from 38 percent in 1994 to 28 percent in 2007-another indication that doctors have been turning to the newer drugs to stave off the use of insulin for as long as possible. 

Although scientists acknowledge that the newer drugs have proven more effective than the older ones in the short term, questions remain as to whether their increased costs are justifiable. 

For one, there is uncertainty as to their ultimate efficacy-will the use of sitagliptin and exenatide, for example, lead to improved outcomes over the long term? The researchers say it is too early to tell if the new drugs will have lasting long-range benefits that justify their costs. For another, scientists emphasize that even the most expensive new drugs cannot replace exercise and a healthy diet as a means of managing the disease.

The researchers published their findings in the October 27, 2008, issue of the Archives of Internal Medicine.

A Statistical Breakdown of the Study's Conclusions

Patient Visits for Type 2 Diabetes Treatments

• 1994: 25 million
• 2007: 36 million

Mean Number of Medications Prescribed Per Diabetes Patient

• 1994: 1.14
• 2007: 1.63

Percent of Patients Receiving Monotherapy

• 1994: 82 percent
• 2007: 47 percent

Percent of Patients Receiving Insulin at Doctor Visits

• 1994: 38 percent
• 2007: 28 percent

(Note: The lowest percentage was 25 percent in 2000) 

Change in Sulfonylurea Use 

• 1994: 67 percent
• 2007: 34 percent

Mean Cost Per Prescription 2001-2007

• 2001: $56
• 2007: $76

Source: HealthDay News