Table 1. Cohort studies on metformin in patients with AAA.

Ref.	AAA patient characteristics	Male sex (%)	Average follow-up (years)	Diabetics (%)	Metformin prescription (%)	Outcome	Difference between using and not using metformin
[77]	Diabetics/untreated AAA (n=58) Age, years: 72.0 (1.0)§	82.7	2.6	100	25.8	Maximum aortic diameter growth	−1.30 (--1.64, −0.96) ‡
[75]	Cohort 1 Patients with AAA (n=1357) Age, years: 73.9 (6.3)§	89.9	3.6	15.9	8.6	Maximum aortic diameter growth	−0.59 (--1.09, −0.09)‡
	Cohort 2 Patients with AAA (n=287) Age, years: 72.6 (7.6)§	81.8	2.9	24.0	13.5	Maximum aortic diameter growth	--1.15 (−2.16, --0.14)‡
	Cohort 3 Patients with AAA (n=53) Age, years: 73.1 (7.4)§	84.9	1	35.8	30.1	Maximum aortic diameter growth	−1.09 (--1.89, −0.29)‡
[78]	Diabetics/unruptured AAA (n=13,843) Age at AAA diagnosis, years: 69.8 (7.8)§	99.4	4.2	100	39.7	Maximum aortic diameters growth	--0.30 (−0.37, --0.23)‡
[79]	Cohort 1 Asymptomatic/unrepaired AAA (n=1080) Age, years: 73.4 (7.2)§	81.5	3.2	21.6	11.9	Incidence of AAA repair or death due to aneurysm rupture AND maximum aortic diameter growth	0.46 (0.26, 0.80)¤
							--0.52 (−0.97, −0.07)‡
	Cohort 2 Asymptomatic/unrepaired AAA (Ø ≤50 mm; n=763) Age, years: 73.5(7.3)§	79.8	3.6	76.2	13.8		0.45 (0.21, 0.96)¤
							−0.68 (--1.37, 0.01)‡
[81]	Cohort 1 – Diabetes/no metformin (n=43.073) Age, years: 72.27 (7.85)§    Cohort 2 – Diabetes/metformin (n=24.361) Age, years: 69.65 (7.15)§	100	5	Cohort 1 and 2 100	36.1	Surgery and/or death after AAA diagnosis	Cohort 1 0.88 (0.85, 0.91)¤
							Cohort 2 0.93 (0.84, 1.04)¤
[80]	Baseline Ø ≥30mm (n = 526) Age, years: 69.0 (5.7)§	94.2	3.2	18.6	12.3	Maximum aortic diameter	−0.50 (--1.05, 0.05)‡
[76]	Patients undergoing AAA repair (n = 306) Age, years: 71.6 (5.8)§	NM	0.1	25.2	17.6	Maximum aortic diameter growth	0.09 (0.02, 0.47)‡

Ø: Aortic diameter; §: Mean (standard error);‡: Mean difference, 95% IC; ¤:Odds ratio, 95% IC; NM: Not mentioned.

Adapted from [82].