While Most Diabetes Drugs Provide Similar Glucose Control, Some Offer Important Advantages
Blood Glucose Control
Most oral medications prescribed for type 2 diabetes are similarly effective for reducing blood glucose, but the drug metformin is less likely to cause weight gain and may be more likely than other treatments to decrease so-called bad cholesterol.
A version of the analysis was posted today in the online version of Annals of Internal Medicine.
The federally funded analysis is based on scientific evidence found in 216 published studies. The report summarizes the effectiveness, risks, and estimated costs for 10 drugs: acarbose (sold as Precose), glimepiride (Amaryl), glipizide (Glucotrol), glyburide (Micronase, DiaBeta, Glynase PresTab), metformin (Glucophage, Riomet, Fortamet), miglitol (Glyset), nateglinide (Starlix), pioglitazone (Actos), repaglinide (Prandin), and rosiglitazone (Avandia).
Type 2 diabetes is an increasingly common chronic disease that occurs in people who have difficulty converting glucose (a sugar) into energy. Blood glucose levels are high either because their cells are resistant to insulin (a hormone that helps convert glucose into energy) or because their pancreas does not produce enough insulin. Diabetes can cause severe problems with the heart, eyes, kidneys, and nerves. Obesity increases the risks of developing type 2 diabetes. From 1980 through 2005, the number of Americans diagnosed with diabetes soared from 5.6 million to 15.8 million.
"As more people are diagnosed with type 2 diabetes and with the growing array of treatment choices, this is a landmark review," said AHRQ Director Carolyn M. Clancy, M.D. "This summary of scientific evidence is not only an important tool for clinicians and patients seeking the most appropriate therapy, but it also points out in what areas we need more research to confront this disease."
As new classes of oral diabetes medications have become available, patients and clinicians have faced a growing list of treatment options. Earlier scientific reviews have highlighted some differences between medications, but AHRQ's new analysis is the first to summarize evidence on the effectiveness and adverse events for all approved oral medications commonly used in the United States for type 2 diabetes.
Diabetes patients typically are monitored with tests that check the percentage of hemoglobin A1c (HbA1c) in their blood. Checking for HbA1c is a more reliable indicator of chronic high blood sugar than checking blood glucose itself. According to the AHRQ review, most diabetes drugs offer about a one point absolute reduction in HbA1c. In those cases, for example, a diabetes patient's HbA1c might drop from 8 to 7 (with 5 being normal in patients who don't have diabetes). Nateglinide, acarbose, and miglitol lower HbA1c by about half that much. Combining diabetes medications, evidence shows, often works better at reducing HbA1c.
AHRQ's analysis of published studies, completed by the Agency's Johns Hopkins University Evidence-based Practice Center in Baltimore, also concluded: