Metformin appears more durable as monotherapy versus sulfonylurea or meglitinide, study finds

Metformin appeared to be effective as monotherapy for a longer period than sulfonylurea or meglitinide in treatment-naïve patients with type 2 diabetes, a recent study reports.

Researchers in Sweden used data from the Swedish National Diabetes Register to examine the durability of oral hypoglycemic agents in patients with type 2 diabetes who were new to drug therapy for their condition. Patients who were registered from July 2005 through December 2011 were followed for 5.5 years. Treatment durability was measured by calculating time to monotherapy failure, which was defined as discontinuation of continuous use with the first prescribed drug, switch to a new drug, or add-on treatment with an additional drug. The study results were published in the March BMJ Open Diabetes Research and Care.

The researchers used a propensity score-matched cohort to balanced baseline characteristics among patients taking sulfonylurea (n=717) versus metformin (n=3,585) and meglitinide (n=218) versus metformin (n=1,090). The mean patient age in all groups was approximately 71 years, and the mean diabetes duration was approximately 5 years. Compared with metformin, sulfonylurea (hazard ratio, 1.74; 95% CI, 1.56 to 1.94) and meglitinide (hazard ratio, 2.52; 95% CI, 1.89 to 3.37) were associated with a higher risk of monotherapy failure overall. Both sulfonylurea and meglitinide were also associated with a higher risk for 2 of the components of the monotherapy failure definition: addition of a new drug (hazard ratios, 3.14 [95% CI, 2.66 to 3.69] and 2.52 [95% CI, 1.89 to 3.37]) and switching to a new drug (hazard ratios, 2.81 [95% CI, 2.01 to 3.92] and 3.78 [95% CI, 2.25 to 6.32]). The 3 drugs did not differ in risk for treatment discontinuation.

The authors noted that residual confounding could have affected their results and that many patients were excluded from the study because of missing data, among other limitations. However, they concluded that most patients with type 2 diabetes who were beginning monotherapy with an oral hypoglycemic agent stopped treatment, switched to a new drug, or began add-on treatment with a second drug during 5.5 years of follow-up. Patients who started monotherapy with sulfonylurea or meglitinide were more likely to switch drugs or add a drug to their treatment than were those who started monotherapy with metformin. “These results strengthen the current evidence of a superior durability with metformin compared with [sulfonylurea] in real life,” the authors wrote. “The results from this study suggest that this also applies when comparing metformin with meglitinide.”