Metformin does not increase risk for Alzheimer's disease

  • Sluggett JK & al.
  • J Clin Endocrinol Metab
  • 28 Nov 2019

  • International Clinical Digest
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Takeaway

  • Metformin use is not associated with increased risk for Alzheimer's disease (AD) in older patients with type 2 diabetes (T2D).

Why this matters

  • Previous studies have linked T2D to increased AD risk, with conflicting results on an association with metformin use.

Study design

  • Researchers in this nested case-control study analysed the health records of community-dwelling adults diagnosed with AD ≥3 years after diabetes (n=9862; mean age, 80.6 [median IQR, 76.3-84.4] years; 59.7% women; diabetes duration, 9.9 [median IQR, 6.2-14.8] years) who were matched with up to 2 patients without AD (n=19,550).
  • Funding:

Key results

  • About three-quarters of all patients received metformin at least once (AD group, 73.3%; control group, 74.3%).
  • Metformin exposure was not associated with incident AD (aOR, 0.99; 95% CI, 0.94-1.05).
  • AD risk was lower among patients receiving long-term and high-dose metformin therapy; specifically:
    • those dispensed metformin for ≥10 years (aOR, 0.85; 95% CI, 0.76-0.95) and
    • those dispensed an average of >2 g metformin daily (aOR, 0.89; 95% CI, 0.82-0.96).

Limitations

  • Data were not available on patient lifestyle factors, BMI, nonpharmacological approaches to diabetes management, medications dispensed during inpatient hospital stays, glycaemic control, and estimated glomerular filtration rates.