The NICE-PAD II Trial

Among people with peripheral artery disease (PAD) age 50 and older, the investigators will test the hypothesis that PAD participants randomized to nicotinamide riboside (NR) will have greater improvement or less decline in six-minute walk distance at six-month follow-up, compared to those randomized to placebo. The study will randomize 250 participants with PAD age 50 and older to one of two groups for six months: nicotinamide riboside vs placebo. Our primary outcome is change in six-minute walk distance at six-month follow-up. Secondary outcomes are Walking Impairment Questionnaire (WIQ) distance score, PROMIS Mobility score, calf muscle perfusion (measured by magnetic resonance arterial spin labeling (MRI ASL)), oxidative stress (measured by plasma oxidized LDL), NAD+ abundance in whole blood, 6-minute walk improvement by baseline whole blood NAD+ levels, and 6-minute walk distance at 4 weeks after intervention completion. To achieve the specific aims, the study will randomize 250 participants age 50 and older with PAD to one of two groups: nicotinamide riboside vs placebo. Participants will be followed for six months, with an additional four-week follow-up period after completion of the study intervention.