Can metformin help improve mental function in patients with type 2 diabetes?

This study looked at whether metformin (Glucophage) therapy improved mental functioning in patients with type 2 diabetes. The authors concluded that metformin significantly improved mental functioning in these patients.

Metformin is recommended as a first-line treatment for patients with type 2 diabetes (T2D). Most patients eventually require second-line medications for better blood glucose control. These include sulfonylureas (SU) and thiazolidinediones (TZD).

The tendency for diabetic patients to have other medical conditions like heart disease can make diabetes management difficult. T2D has also been associated with declining mental function and a higher risk of dementia. Up to 60% of patients with T2D have some decline in mental function. Whether metformin can improve mental function in patients with T2D is controversial.

This study looked at the results of 10 studies. These studies included 254,679 patients treated with metformin. 90,898 patients were treated with TZD. 235,505 patients were treated with SU.

Overall, metformin significantly reduced mental decline by 10%. SU also slightly reduced mental decline by 8%. However, TZD did not have a significant effect on mental decline. The use of insulin significantly increased mental decline by 1.34-fold.

A separate analysis found that metformin significantly improved mental functioning among American (by 31%) and European patients (by 29%). However, metformin was not found to improve mental function among Asian patients.

This study concluded that metformin significantly improved mental functioning in patients with T2D. 

Mental function can change with age and how long a patient has had T2D. Some outside factors may bias these results. Also, the studies analyzed here were all different and had different numbers of patients. More studies are needed.