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Metformin vs. Sulfonylurea To Lower Dementia Risk In T2D

Nov 12, 2019
 
Editor: David L. Joffe, BSPharm, CDE, FACA

Author: Nadeen Ayad, BCPS, PharmD Candidate, Skaggs School of Pharmacy, University of Colorado

A recent study assessing metformin vs. sulfonylurea found important effects on dementia, especially in African American patients, with type 2 diabetes.

Metformin has been the foundation and the preferred initial therapy for the treatment of type 2 diabetes. In addition to lowering blood glucose, it can lower the risk of obesity and reduce the risk of colon cancer in patients with diabetes. Recent studies have shown that metformin may also lower the risk of dementia in African American patients who are at a higher risk of dementia at younger ages with greater decline as compared with white patients. This study was to compare incident dementia risk associated with sulfonylureas compared to metformin among patients with diabetes, and whether the use of metformin may help decrease that risk.

They reviewed medical records of 73,761 patients, including 10,559 African American patients treated at VA hospitals. The mean age of patients was between 58-62 years. Patients were free of dementia diagnoses and any diabetes treatment for two years before cohort entry. Metformin or sulfonylurea monotherapy was used for these patients to treat their T2D.

Researchers found that, after controlling for confounding, metformin use among patients aged > 50 years was associated with a significantly lower risk of dementia in African American patients (HR 0.73 ; 95% CI 0.6- 0.89) but not in white patients ( HR 0.96; 95% CI 0.9-1.03), with the strongest association being between ages 50 to 64 years in African American patients. From the results, in those patients between ages 65 to 74 years, metformin was associated with a  lower risk of dementia in both races. There was no significant difference observed in patients aged > 75 years.

The strength of this study is the use of large data sets to examine the neurological benefits of metformin vs. sulfonylureas. However, this was a retrospective study that looked back at ICD-9 diagnoses, which can leave room for bias and can give an incomplete clinical picture.

In conclusion, metformin appears to be an affordable treatment with the potential of reducing the risk of dementia in patients with type 2 diabetes. The authors concluded that metformin was associated with a significantly lower risk of dementia among younger African American patients compared to sulfonylureas. These findings suggest that physicians should continue to use metformin as initial therapy in patients with type 2 diabetes, especially in the African American population.

Practice Pearls:

  • Metformin is the preferred initial therapy for type 2 diabetes, not only because of its blood glucose-lowering effects, but also due to its cardiovascular and neurological benefits.
  • Seventy-three thousand seven hundred sixty-one patients, including 10,559 African American patients, were initiated on metformin or sulfonylurea monotherapy for the treatment of their type 2 diabetes. Their mean age was 58-62 years.
  • The findings showed that metformin was associated with a significantly lower risk of dementia in patients aged between 50-75 years. The results showed the strongest association was in African American patients aged between 50-64 years. Major differences were not observed in patients aged > 75 years of age.

Reference for ” Metformin vs. Sulfonylurea To Lower Dementia Risk In T2D”:

Scherrer JF, et al. Association between Metformin Initiation and Incident Dementia among African American and White Veterans Health Administration Patients. Ann Fam Med. 2019 Jul/Aug; 17 (4): 352-362.

Nadeen Ayad, BCPS, PharmD Candidate, Skaggs School of Pharmacy, University of Colorado.