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Association between metformin and abdominal aortic aneurysm in diabetic and non-diabetic US veterans
  1. S Scott Sutton1,2,
  2. Joseph Magagnoli1,2,
  3. Tammy H Cummings1,2,
  4. James W Hardin2,3
  1. 1 Clinical Pharmacy and Outcomes Sciences, University of South Carolina, Columbia, South Carolina, USA
  2. 2 Dorn Research Institute, William Jennings Bryan Dorn VA Medical Center, Columbia, South Carolina, USA
  3. 3 Epidemiology and Biostatistics, University of South Carolina, Columbia, South Carolina, USA
  1. Correspondence to Mr Joseph Magagnoli, Clinical Pharmacy and Outcomes Sciences, University of South Carolina, Columbia, SC 29208, USA; magagnol{at}


We sought to examine the progression from abdominal aortic aneurysm (AAA) diagnosis to surgery and death among diabetics with and without exposure to metformin as well as non-diabetics. We conducted a retrospective cohort study (January 2000 to July 2019) comparing 3 transitions (AAA surgery, death, and death after AAA surgery) among propensity score-matched metformin-exposed and unexposed diabetic veterans and non-diabetic veterans using the VA Informatics and Computing Infrastructure database. We fit an adjusted Cox proportional hazards model with transition-specific effects. There were 43,073 metformin-unexposed diabetics, 24,361 metformin-exposed diabetics and 56,006 non-diabetics. Compared with the non-diabetic cohort, both diabetic cohorts have a lower risk of surgery (no metformin (HR=0.740, 95% CI 0.706 to 0.776); with metformin (HR=0.770, 95% CI 0.730 to 0.813)). However, the non-metformin diabetic cohort has a higher risk of death (HR=1.024, 95% CI 1.004 to 1.045) and death after surgery (HR=1.086, 95% CI 1.013 to 1.165). The metformin-exposed diabetic cohort has a lower risk of death in the first 10 years after AAA diagnosis (HR=0.877, 95% CI 0.855 to 0.899), yet a higher risk of death 10 years after AAA diagnosis (HR=1.177, 95% CI 1.092 to 1.270) compared with non-diabetic cohort. Non-diabetics have the highest rate of AAA surgery compared with both diabetic cohorts. However, diabetics without metformin have the highest risk of death prior to, and after surgery. This research provides novel findings for patients diagnosed with AAA. The use of metformin after both AAA diagnosis and surgery should be further investigated.

  • aorta
  • diabetes mellitus

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  • Contributors SSS, JM: conception and design. JM, SSS: acquisition of data. JM: analysis. SSS, JM, TC, JH: manuscript preparation.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Disclaimer This paper represents original research conducted using data from the Department of Veterans Affairs. This material is the result of work supported with resources and the use of facilities at the Dorn Research Institute, WJB Dorn Veterans Affairs Medical Center, Columbia, South Carolina. The contents do not represent the views of the US Department of Veterans Affairs or the US government.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The study was conducted in compliance with the Department of Veterans Affairs requirements and received Institutional Review Board and Research and Development approval (project number 1139248-1).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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