Because of the increased number of patients, growing reliance on multiple medications and the shift toward more expensive new medicines, the annual cost of diabetes drugs nearly doubled in only six years, rising from $6.7 billion in 2001 to $12.5 billion in 2007. The single greatest contributor was the use of newer, more expensive medications.

In 2000, more than 11 million Americans had been diagnosed with diabetes, according to background information in the article. "By 2050, the number of Americans with diabetes is expected to soar to 29 million, a prevalence of 7 percent," the authors write. "The annual economic burden of diabetes is estimated at $132 billion and increasing. In 2002, more than one-tenth of U.S. health care expenditures were attributable to diabetes." As costs and prevalence increase, managing diabetes also has become increasingly complex, as physicians prescribe more medications to each patient and combine drugs from different therapeutic classes.

To evaluate these trends, G. Caleb Alexander, M.D., M.S., of the University of Chicago Hospitals, and colleagues gathered diabetes prescription information and costs from national databases. The researchers analyzed prescription data from U.S. patients age 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.

The analysis revealed that, between 1994 and 2007:

• The estimated number of yearly patient visits to treat diabetes increased from 25 million to 36 million
• The average number of medications prescribed per treated patient increased from 1.14 to 1.63
• Among visits in which any treatment was given, the number in which only one drug was prescribed decreased from 82 percent to 47 percent
• Insulin use decreased from 38 percent in 1994 to a low of 25 percent in 2000, and then increased again to 28 percent

The types of medications prescribed shifted—the use of sulfonylurea drugs decreased from 67 percent to 34 percent of treatment visits, while use of newer drugs such as biguanides and glitazones increased, so that by 2007 these agents were prescribed at 54 percent and 28 percent of treatment visits, respectively

The increasing use of glitazones—along with other new treatments, including new forms of insulin and other new classes of drugs—accounted for increases in average cost per prescription (from $56 in 2001 to $76 in 2007) and in overall medication expenditures for those with diabetes (from $6.7 billion in 2001 to $12.5 billion in 2007).

"We document large shifts in patterns of diabetes treatment and pharmaceutical expenditures across treatment classes," the authors conclude. "Whether increased treatment costs are balanced by improved outcomes associated with these changes cannot be evaluated in the absence of data comparing effectiveness and cost-effectiveness across treatment classes. Our findings suggest the importance of generating new comparative data and coupling this information with clinical and formulary guidelines that contribute to constraining costs, maximizing glycemic control and minimizing diabetes-related morbidity and mortality."

Dr. Alexander is a Robert Wood Johnson Faculty Scholar and is also supported by a career development award from the Agency for Healthcare Research and Quality. Senior author Dr. Stafford was supported by a Mid-Career Mentoring Award from the National Heart, Lung, and Blood Institute.

Note: If no author is given, the source is cited instead.

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