BACKGROUND: Recently, the usefulness of metformin as an oral hypoglycemic agent has been re-evaluated, while secondary failure of long-term treatment with sulfonylurea (SU) has become a serious problem. In this study, the usefulness of combination therapy with metformin was evaluated in patient with non-obese type 2 diabetes mellitus showing secondary failure of treatment with SU.
PATIENTS AND METHODS: Twenty non-obese patients with type 2 diabetes mellitus showed HbA1c levels of 7% or over despite more than 5 years of treatment with SU. Metformin was administered to these patients at a dose of 500 mg/day for 3 months in combination with SU, and glycemic control was compared before and after combination therapy.
RESULTS: After combination therapy, the mean plasma glucose level obtained 2 hours postprandial was significantly decreased by 20.0% (216±41.7 mg/dl vs. 172.0±47.7 mg/dl, p<0.001) . In addition, the mean HbA1c level was significantly decreased by 8.8% (8.0±0.8% vs. 7.3±0.8%, p<0.001) . However, the mean IRI level, the mean body mass index, and mean plasma lipid levels did not significantly change after combination therapy.
CONCLUSIONS: These findings suggest that combination therapy with metformin is useful for improving blood glucose levels without enhancing insulin secretion in patients with non-obese type 2 diabetes mellitus who showed secondary failure of treatment with SU. However, further studies are needed to confirm whether this combination therapy will contribute to delaying the introduction of insulin therapy.
Japan Primary Care Association