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Note: This report is greater than 5 years old. Findings may be used for research purposes but should not be considered current.
This report is from AHRQ's Data Points Publication Series.
Biguanides (i.e., metformin) were the most commonly used antidiabetic drug class among Medicare beneficiaries from 2006 to 2009, followed by sulfonylureas, insulins, and thiazolidinediones. Approximately 37 percent of diabetic beneficiaries had a claim for a biguanide in 2009.
Sulfonylurea use generally increased with age. Among Medicare beneficiaries age 85 years or older, sulfonylureas were used more frequently than both biguanides and insulins from 2006 to 2009.
From 2006 to 2009, thiazolidinedione use decreased dramatically overall and uniformly across all health care referral regions in the U.S. This trend was consistent among all age groups.
Diabetes mellitus, a condition characterized by high blood glucose, is a major public health burden. The condition affects an estimated 7.8 percent (23.6 million persons) of the United States population and accounts for more than $174 billion annually in excess health care costs. Type 2 diabetes, where the pancreas gradually loses the ability to produce insulin in response to meals and peripheral tissues fail to properly respond to insulin (insulin resistance), comprises the vast majority of all cases of diabetes in the U.S. It is strongly associated with obesity and age over 45 years. Older people with diabetes are more likely to experience cognitive disorders, urinary incontinence, and physical disabilities such as impaired mobility and tremor than the general population. They are more likely to suffer cognitive decline and inadequate physical function than people in younger age categories, even after adjusting for preexisting conditions. Additionally, older adults with diabetes are more likely to have multiple medical conditions and are twice as likely to have depression than nondiabetic elders. Finally, they are also significantly more likely to be affected by hypoglycemia.
There are currently six classes of oral antidiabetic medications: alpha-glucosidase inhibitors, biguanides, dipeptidyl peptidase-4 inhibitors, meglitinides, sulfonylureas, and thiazolidinediones. Several types of insulin and other injectable drugs such as amylin analogs and glucagon-like peptide-1 receptor agonists are also available. The American Diabetes Association (ADA) guidelines and the Effective Healthcare Program generally suggest metformin as a first-line therapy for treating type 2 diabetes until kidney function has declined to a certain point. Second-line therapies include combinations of metformin and insulin, or metformin and a sulfonylurea.
Metformin is also frequently avoided in older adults due to declines in renal function as indicated by product labeling, though some data suggest that this precaution is not warranted. Additionally, sulfonylurea use in older adults is associated with increased risk of hypoglycemia also due to decreasing renal function.
Recent findings regarding rosiglitazone also have implications for older people. In 2007, rosiglitazone, a thiazolidinedione, was found to be associated with myocardial infarction, major adverse cardiovascular events, mortality from cardiovascular causes, and all-cause mortality. A more recent study comparing rosiglitazone with pioglit-azone, also a thiazolidinedione, confirms these results. However, pioglitazone has been associated with a small but significantly increased risk of developing heart failure. Prescription patterns for rosiglitazone changed dramatically when the 2007 meta-analysis was published and the Food and Drug Administration initially issued warnings about the safety of rosiglitazone. A recent study showed up to a 54 percent decrease in rosiglit-azone prescription claims across nine commercial plans covering 9 million eligible members, though pioglitazone use was not shown to have changed significantly.
The goals of this report are to: (1) present general antidiabetic drug utilization patterns among the Medicare Parts A and B fee-for-service (FFS) population enrolled in Medicare Part D; and (2) focus on the utilization of the four most frequently dispensed antidiabetic drug classes in this same population: biguanides, sulfonylureas, insulins, and thiazolidinediones.
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