How Much Does Metformin Lower HbA1c Level?

On average, by about 1% more than various alternatives.

How much lowering of glycosylated hemoglobin (HbA_1c) levels should we expect when we prescribe metformin to patients with diabetes? To answer this question, researchers performed a meta-analysis of 35 randomized metformin trials of ≥12 weeks' duration. Key findings are as follows:

In comparisons between metformin monotherapy and placebo (or no drug treatment), metformin reduced mean HbA_1c level by 1.1%.
In comparisons involving metformin plus another oral agent versus the other agent alone, addition of metformin reduced mean HbA_1c level by 1.0%.
In comparisons involving metformin plus insulin versus insulin alone, addition of metformin reduced mean HbA_1c level by 0.8% in patients with type 2 diabetes. In patients with type 1 diabetes receiving…

Reviewing Author

Allan S. Brett, MD

Disclosures

Nothing to disclose

Allan S. Brett, MD

Disclosures

Nothing to disclose

How Much Does Metformin Lower HbA_1c Level?

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Reviewing Author