Physical Performance in Peripheral Arterial Disease: A Slower Rate of Decline in Patients Who Walk More

3 January 2006 | Volume 144 Issue 1 | Pages 10-20

Background: Exercise rehabilitation programs increase treadmill walking performance in patients with peripheral arterial disease (PAD) and intermittent claudication. However, it is unknown whether patients with PAD who walk for exercise regularly have less functional decline than those with less walking activity.

Objective: To determine whether patients with PAD who report that they walk for exercise 3 or more times per week have less annual functional decline than those who walk for exercise less frequently.

Design: Prospective cohort study with a median follow-up of 36 months (interquartile range, 24 to 36 months).

Setting: Academic medical center.

Participants: 417 men and women with PAD.

Measurements: Participants were classified at baseline and annually according to the number of times they reportedly walked for exercise each week. Functional assessments (6-minute walk distance, 4-meter walking speed, summary performance score) were measured at baseline and annually. Results were adjusted for age, sex, ethnicity, comorbid conditions, body mass index, ankle–brachial index, education, leg symptoms, cigarette use, geriatric depression score, previous year's level of functioning, and patterns of missing data.

Results: Compared with those who exercised less frequently, patients who walked for exercise 3 or more times per week had a significantly smaller average annual decline in 6-minute walking distance (–48.0 feet per year compared with –56.6 feet per year for those who walked 1 to 2 times per week and –79.4 feet per year for nonexercisers; P for trend = 0.037). Patients who walked for exercise at least 3 times per week experienced a smaller average annual decline in the usual-paced 4-meter walking velocity (–0.014 m/s per year compared with –0.022 m/s per year for those who walked 1 to 2 times per week and –0.045 m/s per year for nonexercisers; P = 0.005). Similar findings were observed for the fast-paced 4-meter walk. The subset of asymptomatic patients who walked for exercise 3 or more times per week had annual declines in 6-minute walking performance (P = 0.107), normal-paced walking velocity (P = 0.065), and the summary performance score (P = 0.115); however, these declines were smaller than those observed in asymptomatic participants who walked fewer than 3 times per week.

Limitations: Because this was an observational study, associations reported here cannot be construed as causal relationships. Sample sizes for subgroup analyses were small, which limited statistical power.

Conclusion: Among patients with PAD, self-directed walking exercise performed at least 3 times weekly is associated with significantly less functional decline during the subsequent year. Similar trends were observed in the subset of asymptomatic patients with PAD. These findings may be particularly important for the numerous patients with PAD who do not have access to supervised walking exercise programs.

Editors' Notes Context Patients with lower-extremity peripheral arterial disease (PAD) benefit from supervised walking programs, but cost, travel, and other factors often limit participation. Contribution This prospective study shows that a self-directed program of walking at least 3 times per week for exercise is associated with a significantly reduced functional decline during the subsequent year in patients with PAD when compared with those who walk less frequently. Implications Self-directed walking for exercise may benefit a much larger proportion of patients with PAD than is currently being served by supervised rehabilitation programs. Cautions Observational studies, such as this one, cannot prove a causal relationship between walking frequency and functional decline. —The Editors

 

Author and Article Information

From Northwestern University Feinberg School of Medicine, Chicago, Illinois; Evanston Northwestern Hospital, Evanston, Illinois; National Institute on Aging, Baltimore, Maryland; and University of California at San Diego, La Jolla, California.

Potential Financial Conflicts of Interest: None disclosed.

Grant Support: By the National Heart, Lung, and Blood Institute (grant numbers R01-HL58099 and R01-HL64739) and by the National Center for Research Resources, National Institutes of Health (grant number RR-00048).

Requests for Single Reprints: Mary M. McDermott, MD, 675 North St. Clair, Suite 18-200, Chicago, IL 60611; e-mail, mdm608{at}northwestern.edu.

Current Author Addresses: Drs. McDermott and Martin: 675 North St. Clair, Suite 18-200, Chicago, IL 60611.

Drs. Liu, Greenland, and Tian and Mr. Tan: 680 N. Lake Shore Drive, Suite 1102, Chicago, IL 60611.

Dr. Ferrucci: National Institute on Aging, Clinical Research Branch, Harbor Hospital, 3001 South Hanover Street, Fifth Floor, Baltimore, MD 21225.

Dr. Criqui: University of California at San Diego, Family & Preventive Medicine, 9500 Gilman Drive, La Jolla, CA 92093.

Dr. Guralnik: National Institute on Aging, Gateway Building, Room 3-C309, 7201 Wisconsin Avenue, Bethesda, MD 20892.

Dr. Schneider: Evanston Northwestern Hospital, Department of Surgery, 2650 Ridge Avenue, Burch 100, Evanston, IL 60201.

Dr. Pearce: 201 East Huron, Suite 10-105, Chicago, IL 60611.

Author Contributions: Conception and design: M.M. McDermott, K. Liu, L. Ferrucci, P. Greenland, J.M. Guralnik, J.R. Schneider, G.J. Martin.

Analysis and interpretation of the data: M.M. McDermott, K. Liu, L. Ferrucci, M.H. Criqui, P. Greenland, J.M. Guralnik, L. Tian, J. Tan, G.J. Martin.

Drafting of the article: M.M. McDermott, M.H. Criqui.

Critical revision of the article for important intellectual content: M.M. McDermott, L. Ferrucci, M.H. Criqui, P. Greenland, J.M. Guralnik, J.R. Schneider, G.J. Martin.

Final approval of the article: M.M. McDermott, K. Liu, M.H. Criqui, P. Greenland, J.M. Guralnik, L. Tian, J.R. Schneider, W.H. Pearce, J. Tan, G.J. Martin.

Provision of study materials or patients: J.R. Schneider, W.H. Pearce, G.J. Martin.

Statistical expertise: K. Liu, L. Tian.

Obtaining of funding: M.M. McDermott, K. Liu, M.H. Criqui, G.J. Martin.

Administrative, technical, or logistic support: W.H. Pearce, J. Tan.

Collection and assembly of data: M.M. McDermott, W.H. Pearce.

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