Results Summary

What was the research about?

About 8.5 million Americans ages 40 or older live with peripheral arterial disease, or PAD. This health problem partially or completely blocks blood vessels, usually those that deliver needed oxygen to the legs. PAD often causes calf pain during walking.

Treatment for PAD aims to improve blood flow. The American Heart Association recommends noninvasive treatments, including exercise therapy, aids to help patients quit smoking, and certain medicines. Antiplatelet medicines prevent blood clots. Statin medicines lower cholesterol levels. Invasive procedures, such as stents or surgery to open or bypass blocked vessels, can also treat PAD.

Over a year, the research team carried out three separate comparisons of treatment approaches:

  • Patients receiving invasive treatment after their first clinic visit versus patients receiving only noninvasive treatment
  • Patients receiving both antiplatelet and statin medicines versus patients receiving only one or none of these medicines
  • Patients receiving all four American Heart Association recommended treatments—antiplatelet and statin medicines, exercise therapy, and aids to stop smoking—versus patients not receiving all four treatments

The research team asked patients with new or worsening PAD-related leg problems questions about their health status, including PAD symptoms, ability to function, quality of life, and satisfaction with care.

What were the results?

Invasive treatment. At the beginning of the study, health status was worse in patients who received invasive treatment than in patients who received noninvasive treatment. But health status in both groups of patients ended up being similar 3, 6, and 12 months after the first visit.

Antiplatelet and statin medicines. At the first visit and at three and six months, health status was better in patients taking both medicines compared with patients who weren’t taking both. At 12 months, health status was similar in the two groups.

Antiplatelet and statin medicines, exercise therapy, and aids to stop smoking. At the first visit, health status was similar in patients who received all four treatments and those who didn’t. At three months, health status was better in people receiving all four treatments. Then at 6 and 12 months, health status in the two groups was similar.

Patient characteristics. At all visits, men had better health status than women. White patients had better health status than patients who were races other than white.

Who was in the study?

The study included 797 adults with PAD of the legs. Of these patients, 42 percent were women, and 28 percent were races other than white. All patients had new or worsening symptoms. The patients received care at 10 clinics focused on PAD. The clinics were in big cities in seven states.

What did the research team do?

The research team selected patients at their first visit to a PAD clinic. The patients completed a survey about their health status related to PAD at the first visit and again after 3, 6, and 12 months. The research team also collected information about the patients, such as their sex and race, and about treatments received during the study.

What were the limits of the study?

The study included only patients with PAD severe enough to be referred to a specialized clinic. These patients received care in only 10 clinics in seven cities. The results may be different for people who have less severe symptoms or who live in other places.

Only about 5 percent of patients received all four recommended treatments. Patients who received all four treatments may differ from patients who didn’t. Results may be different if more patients had received all four treatments. Future research could examine why not many patients received all four recommended treatments.

How can people use the results?

Health status improved in patients, no matter which treatment patients received. Patients and doctors may use these results to inform discussions about treatments for PAD.

Final Research Report

View this project's final research report.

Journal Citations

Related Journal Citations

Peer-Review Summary

Peer review of PCORI-funded research helps make sure the report presents complete, balanced, and useful information about the research. It also confirms that the research has followed PCORI’s Methodology Standards. During peer review, experts who were not members of the research team read a draft report of the research. These experts may include a scientist focused on the research topic, a specialist in research methods, a patient or caregiver, and a healthcare professional. Reviewers do not have conflicts of interest with the study.

The peer reviewers point out where the draft report may need revision. For example, they may suggest ways to improve how the research team analyzed its results or reported its conclusions. Learn more about PCORI’s peer-review process here.

In response to peer review, the PI made changes including

  • Completing multivariate analyses to account for repeated measures. These analyses were initially planned by the researchers, but did not appear to have been carried out before peer review, and reviewers were concerned that univariate analyses could be misinterpreted given the relationships among the outcome variables. The researchers also completed multivariate analyses focusing on one-year health status outcomes that help understand the importance of variables that predict patients' one-year health status outcomes.
  • Addressing reviewer concerns about the handling of missing data by providing a more extensive description of actions that the researchers took to reduce the frequency of missing data, and using a multiple-imputation approach to account for missing data. The PI indicated that this approach was appropriate because missing data were infrequent in the analyses.
  • Providing details on the sites that were included in the study, and why they were included. The researchers stressed their intentions of focusing on sites with sicker patients who they believed would benefit most from treatment.

Conflict of Interest Disclosures

Project Information

Kim G. E. Smolderen, PhD
Saint Luke's Hospital
$1,693,502
10.25302/4.2019.CE.13046677
Patient-Centered Outcomes Recovery from Treating Peripheral Arterial Disease: Investigating Trajectories (PORTRAIT) - Phase II

Key Dates

September 2013
April 2018
2013
2018

Study Registration Information

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Intervention Strategy Intervention Strategies PCORI funds comparative clinical effectiveness research (CER) studies that compare two or more options or approaches to health care, or that compare different ways of delivering or receiving care. View Glossary
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Last updated: January 20, 2023