Can metformin treat abdominal aortic aneurysm disease?

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Takeaway

  • Pending prospective clinical trial confirmation, metformin may be a therapeutic option for limiting progression of early abdominal aortic aneurysm (AAA) disease.

Why this matters

  • AAA rupture risk increases with increasing aortic diameter.
  • No available medication minimizes progressive diameter enlargement or prevents eventual rupture.

Study design

  • Participants were 13,843 patients with asymptomatic AAA disease and diabetes in the Veterans Affairs Health Care System, 2003-2013, with 58,833 radiographic records, of whom 39.7% were prescribed metformin.
  • A subcohort of 7462 patients with baseline AAA diameter 3.5-4.9 cm had 33,418 radiographic studies.
  • Funding: NIH.

Key results

  • Mean imaging follow-up interval was 4.2 years.  
  • Average baseline AAA diameter was 38.0 mm.
  • After adjustment for comorbidities, metformin decreased yearly AAA growth rate by 0.23 mm/year in 1 model analysis and by 0.20 mm/year in another (both P<.001>
  • In subcohort with starting AAA size 35-49 mm and adjusted for comorbidities, metformin decreased yearly AAA growth rate by 0.27 and 0.21 mm/year in the 2 analyses, respectively (both P<.001>

Limitations

  • 99% of participants were men.
  • Heterogeneity in diameter reporting.
  • Inability to stratify AAA results by lab values or diabetes duration.
  • Assumption of no change in metformin prescriptions or other clinical parameters.
  • Insulin prescription status not evaluated.