Can metformin help reduce the risk of developing neurodegenerative disease in elderly patients with T2D?

This study examined if metformin (Glucophage) helped reduce the risk of neurodegenerative disease in elderly patients with Type 2 diabetes (T2D). The authors found that patients taking metformin for more than two years had a lower risk of brain degeneration diseases compared to patients not taking metformin.

Metformin (Glucophage) is typically recommended as a first-line treatment for patients with T2D. Although metformin can help lower blood sugar levels, long-term complications can occur. T2D can lead to dementia and brain degeneration diseases, such as Alzheimer’s disease and Parkinson’s disease. Studies have found that having T2D increases the risk of these diseases by about 1.5-fold.

Several studies have examined if metformin affects brain function, but the results are inconclusive. Some studies have also suggested that long-term use of metformin may slightly increase the risk of Alzheimer's disease. Whether metformin is associated with a lower risk of brain degeneration diseases in elderly patients with T2D is unclear.

This study included the medical records of 5330 elderly patients with T2D. Patients were on metformin therapy for different amounts of time. 15.42% of patients were on metformin for less than one year, and 9.36% were on metformin for 1 to 2 years. 13.05% were on metformin for 2 to 4 years, and 12.67% were on metformin for over four years. Patients were followed-up for an average of 5.2 years.

Overall, 7.16% of patients were diagnosed with brain degeneration diseases. This included dementia (5.52%, 334 patients), Parkinson's disease (1.65%, 100 patients), and Alzheimer's disease (1.17%, 71 patients).

Taking metformin for two years or more was significantly associated with a lower risk. 2 to 4 years of treatment was significantly associated with a 38% lower risk. More than four years of treatment was significantly associated with an 81% lower risk.

Compared to patients who did not take metformin at all, patients taking metformin for 2 to 4 years had a 45% lower risk of dementia. For patients taking metformin for four years or more, this risk decreased even more (78%). Only four years or more of metformin treatment was significantly associated with a lower risk of Parkinson's disease (96%) or Alzheimer's disease (83%).

This study concluded that long-term metformin therapy was significantly associated with a lower risk of brain degeneration diseases in elderly patients with T2D.

This study was retrospective, as it collected data from electronic medical records. Over 97% of patients in the study were men, so these results may not be generalizable to women. More studies are needed to confirm the potential protective effects of metformin on the brain.

Talk to your doctor if you have questions about the potential complications of T2D.