A new study published Wednesday in JAMA Network Opens shows that stopping metformin is linked with increased dementia incidence.
Previous research indicates that metformin can lower the incidence of dementia. People tend to stop taking metformin for their diabetes because of kidney issues or other less severe adverse effects. Researchers wanted to know if there was a link between dementia and ceasing metformin for reasons unrelated to kidney function.
A team from Kaiser Permanente Northern California examined 12,220 people who stopped taking metformin. Of them, 5,640 were women who started metformin at the mean age of 59.4. The participants had normal estimated glomerular filtration rate (eGFR), a marker of kidney function.
The researchers compared the data of the people who stopped taking metformin to 29,126 still on metformin or those who had stopped it after abnormal eGFR levels. The researchers checked HbA1c levels and insulin usage at one and five years after termination in those who stopped metformin to see how they fared in the longer term.
Most of this association between stopping metformin and dementia was not accounted for by increases in HbA1c levels or insulin use one or five years after people stopped taking metformin. People who stopped metformin had 1.21 times the risk of dementia diagnosis compared with those who didn’t stop taking it.
The findings suggest that mechanisms other than glucose control or insulin use may mediate the link between dementia and stopping metformin. The authors said that people at high risk for dementia who have diabetes may be better served by trying to mitigate or manage adverse effects from metformin, such as going on slower-release formulations or taking the drug in the evening with food. This way, the people with diabetes can stay on metformin and reap the benefits that show it’s linked to lower dementia incidence.
