The use of an older class of drugs for type 2 diabetes, the glitazones, is linked to a 22% reduction in the risk of dementia, reveals a long-term study published in the journal “BMJ Open Diabetes Research & Care”.
These drugs can effectively prevent dementia in high-risk patients with mild or moderate type 2 diabetes, and may now be worth prioritizing in future clinical trials to see if they can be reused, the researchers suggest.
Because type 2 diabetes and dementia share some of the same physiological patterns, researchers have begun to study whether diabetes drugs might also help prevent or treat dementia. But to date, the results have been inconsistent.
To shed more light on this question, this study compared the risk of dementia in older people with type 2 diabetes and treated with a sulfonylurea or a thiazolidinedione (TZD) with those treated with metformin alone.
Linked to an 11% lower risk of Alzheimer’s disease and a 57% lower risk of vascular dementia
They were based on the electronic medical records of 559,106 people diagnosed with type 2 diabetes from the Veterans Affairs National Health System (VA), covering the period between January 2000 and December 2019.
Only older patients (at least 60 years) who were first prescribed metformin, or a sulfonylurea (tolbutamide, glimepiride, glipizide, or glyburide), or a glitazone (rosiglitazone or pioglitazone) between January 2001 and December 2017 (559,106). Their health was tracked for an average of almost 8 years.
After at least 1 year of pharmacological treatment, the use of a glitazone alone was associated with a 22% lower risk of dementia from any cause, compared with the use of metformin alone.
Specifically, it was linked to an 11% lower risk of Alzheimer’s disease and a 57% lower risk of vascular dementia.
Since the vascular diseases increase the risk of Alzheimer’s disease, glitazones may help reduce dementia and Alzheimer’s disease in part through their favorable effects on the vascular system, the researchers say.
While the risk of dementia from any cause was 11% lower with the combined use of metformin and glitazones, it was 12% higher with the use of a sulfonylurea drug alone, leading the researchers to suggest that supplementing a sulfonylurea with metformin or a glitazone could partially offset these effects.
Further analysis indicated that those younger than 75 benefited more from a glitazone than older patients, underscoring the importance of early dementia prevention, the researchers say. And these drugs also appeared to be more protective in patients who were overweight or obese.
This is an observational study, so definitive conclusions about cause and effect cannot be drawn. In addition, the researchers acknowledge that some potentially influential information, such as the renal function and the factors geneticand that study participants were predominantly male and white.
However, they suggest that in future studies of reuse of antidiabetes drugs for the prevention of dementia, the possibility of giving priority to glitazones could be considered, based on their results.
They conclude: “These findings may help inform medication selection for patients at high risk of dementia.”