Table 1 Inclusion and exclusion criteria

Inclusion criteria: subjects must meet all the following

Male and female Veterans > 35 and < 89 years of age

Symptoms of intermittent claudication

Diagnosis of PAD as defined by ABI < 0.9 or \(\ge\) 0.9 with evidence of PAD as documented by pulse volume recordings (within 180 days prior to expected randomization)

Medically stable, optimal medical therapy (\(>\) 3 months prior to randomization)

Maximum Walking Distance (MWD) on the 6-min walk test (6MWT) of ≥ 50 m with onset of pain before or at 400 m without the use of a walker

Exclusion criteria: subjects cannot possess any of the following

 General

Investigator expects inclusion could cause harm to subject

Currently taking metformin or have taken metformin (within 180 days of expected randomization date)

Medical condition that will limit ability to ambulate other than PAD or life expectancy (angina, congestive heart failure, pulmonary disease requiring continuously supplemented oxygen, malignancy requiring treatment, etc.)

 Pre-existing diabetes

Type I or II Diabetes Mellitus

HemoglobinA1c > 6.5 (within 180 days of expected randomization date)

 Claudication

Prior above or below knee amputation

Planned hospital admission, major operation, or lower extremity revascularization (< within 12 months after expected randomization date)

Critical limb threatening ischemia (define by non-healing wounds and/or rest pain)

Prior major operation or lower extremity revascularization (within the 3 months before expected randomization date)

 HRQoL testing participation

Non-English speaking

Dementia

 Metformin safety

Kidney disease (dialysis dependence and/or estimated glomerular filtration rate < 45 within 180 days of expected randomization date)

Planned iodinated contrasted imaging study (within the 3 months of expected randomization date)

Acute or chronic metabolic acidosis with or without coma

Women who are pregnant or breast feeding

Unable to swallow uncrushed study drug pills

Enrollment in another greater than minimal risk study