Testing cocoa flavanols for improving walking distance in patients with peripheral artery disease

COCOA Flavanols to Improve Walking Performance in PAD: the COCOA-PAD II Trial

Phase 3 Interventional Northwestern University · NCT04794530

This study is testing if cocoa flavanols can help older adults with peripheral artery disease walk farther and improve their overall mobility.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment190 (estimated)
Ages55 Years and up
SexAll
SponsorNorthwestern University Academic / other
Locations3 sites (Chicago, Illinois and 2 other locations)
Trial IDNCT04794530 on ClinicalTrials.gov

What this trial studies

This trial investigates the effects of cocoa flavanols on improving walking distance in older adults with peripheral artery disease (PAD). Participants aged 55 and older will be randomly assigned to receive either cocoa flavanols or a placebo for six months. The primary outcome measured will be the change in six-minute walk distance, while secondary outcomes will include various physical activity metrics and muscle characteristics. The study aims to enroll 190 participants to assess the potential benefits of cocoa flavanols in enhancing mobility and vascular health.

Who should consider this trial

Good fit: Ideal candidates are individuals aged 55 and older diagnosed with peripheral artery disease.

Not a fit: Patients with critical limb ischemia or those who are wheelchair-bound or require a walker for ambulation may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved mobility and quality of life for patients with peripheral artery disease.

How similar studies have performed: Previous studies have shown promise in using cocoa flavanols for vascular health, suggesting potential for success in this approach.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Age 55 and older
2. Presence of peripheral artery disease (PAD). PAD will be defined as either:

   1. An ABI \<= 0.90 at baseline.
   2. Vascular lab evidence of PAD (such as a toe brachial pressure \< 0.70 or an ankle brachial index less than or equal to 0.90), or angiographic evidence of PAD defined as at least 70% stenosis of an artery supplying the lower extremities.
   3. An ABI of \>0.90 and \<=1.00 who experience a a 20% or greater drop in ABI in either leg after the heel-rise test will also be included.

Exclusion Criteria:

1. Above- or below-knee amputation
2. Critical limb ischemia
3. Wheelchair confinement or requiring a walker to ambulate
4. Walking is limited by a symptom other than PAD
5. Current foot ulcer on bottom of foot
6. Failure to successfully complete the one-week study run-in
7. Planned major surgery, coronary or leg revascularization during the next eight months
8. Major surgery, coronary or leg revascularization or major cardiovascular event in the previous three months
9. Major medical illness including lung disease requiring oxygen, Parkinson's disease, a life-threatening illness with life expectancy less than eight months, or cancer requiring treatment in the previous two years. \[NOTE: potential participants may still qualify if they have had treatment for an early stage cancer in the past two years and the prognosis is excellent. Participants who require oxygen only at night may still qualify.\]
10. Mini-Mental Status Examination (MMSE) score \< 23
11. Allergy to the study intervention
12. Potential participants who have taken cocoa supplements in previous three months, are unwilling to avoid taking cocoa flavanol supplements, or are consuming dark chocolate regularly (i.e. approximately 1.5 ounces of dark chocolate more than three times per week, or more than 4.5 ounces per week).
13. Non-English speaking
14. Participation in or completion of a clinical trial in the previous three months. \[NOTE: after completing a stem cell or gene therapy intervention, participants will become eligible after the final study follow-up visit of the stem cell or gene therapy study so long as at least six months have passed since the final intervention administration. After completing a supplement or drug therapy (other than stem cell or gene therapy), participants will be eligible after the final study follow-up visit as long as at least three months have passed since the final intervention of the trial.\]
15. Visual impairment that limits walking ability
16. Six-minute walk distance of \<500 feet or \>1600 feet.
17. Participation in a supervised treadmill exercise program in previous three months
18. Unable to tolerate caffeine
19. In addition to the above criteria, investigator discretion will be used to determine if the trial is unsafe or not a good fit for the potential participant

Where this trial is running

Chicago, Illinois and 2 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Peripheral Artery Diseasecocoa flavanols
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.