More Evidence Metformin May Be Neuroprotective

Megan Brooks

October 31, 2023

TOPLINE:

New research suggests terminating metformin may raise the risk for dementia in older adults with type 2 diabetes, providing more evidence of metformin’s potential neuroprotective effects.

METHODOLOGY:

• Researchers evaluated the association between discontinuing metformin for reasons unrelated to kidney dysfunction and dementia incidence.
• The cohort included 12,220 Kaiser Permanente Northern California members who stopped metformin early (with normal kidney function) and 29,126 routine metformin users.
• The cohort of early terminators was 46% women with an average age of 59 years at the start of metformin prescription. The cohort continuing metformin was 47% women, with a start age of 61 years.

TAKEAWAY:

• Adults who stopped metformin early were 21% more likely to be diagnosed with dementia during follow up (hazard ratio, 1.21; 95% CI, 1.12 – 1.30), compared with routine metformin users.
• This association was largely independent of changes in A1c level and insulin usage.

IN PRACTICE:

The findings “corroborate the largely consistent evidence from other observational studies showing an association between metformin use and lower dementia incidence [and] may have important implications for clinical treatment of adults with diabetes,” the authors write.
SOURCE:

The study, with first author Scott Zimmerman, MPH, University of California San Francisco, was published online October 25 in JAMA Network Open.
LIMITATIONS:

Dementia diagnosis was obtained based on medical records. Factors such as race, ethnicity, or time on metformin were not evaluated. Information on the exact reason for stopping metformin was not available.
DISCLOSURES:

The study was funded by grants from the National Institutes of Health, National Institute on Aging. Zimmerman owns stock in AbbVie Inc, Gilead Sciences LLC, CRISPR Therapeutics, and Abbott Laboratories. Disclosure for the other study authors can be found with the original article.