Early initiation of metformin reduced risk for failure

Metformin worked nearly twice as long for patients with diabetes who began taking the drug within three months of their diagnosis, new study data indicated.

“This study suggests that to gain full benefit from metformin, patients should start taking it as soon as they find out they have diabetes,” researcher Jonathan B. Brown, PhD, of the Kaiser Permanente Center for Health Research, Portland, Ore., said in a press release.

Brown and colleagues used electronic health records to follow 1,799 patients with type 2 diabetes included in Kaiser Permanente’s health plan in Washington and Oregon for up to five years. All patients had lowered their HbA1c to less than 7% after initiating metformin as their first-ever antihyperglycemic drug.

Metformin failure was defined as an HbA1c level of at least 7.5% or when a patient started taking a second antihyperglycemic agent.

Of 1,799 patients, 42% experienced secondary failure of metformin within the two- to five-year follow-up period. The mean failure rate was 17% per year.

Metformin failed at a rate of 12.2% per year for patients who started the drug within three months after diabetes diagnosis compared with a failure rate of 21.3% for patients who started the drug within one to two years after diagnosis and 21.9% for those who started the drug three years after diagnosis.

Younger age, longer duration of diabetes before therapy and higher HbA1c at metformin initiation were further associated with metformin failure. The researchers said other unmeasured factors may have also influenced the results.

“Starting the drug early preserves the body’s own ability to control blood sugar, which in turn prevents the long-term complications of diabetes,” researcher Gregory A. Nichols, PhD, also of the Kaiser Permanente Center for Health Research, said in the release.

This is the first study to compare metformin failure rates in a real-world, clinical practice setting; other studies compared metformin failure rates only in clinical trials, according to the researchers.

The researchers said these data “support the current treatment algorithm for hyperglycemia management that recommends metformin initiation when diabetes is first diagnosed.”

Brown JB. Diabetes Care. 2010;33:501-506.