June 19th, 2012

New Uses Found for a Traditional Walking Test

The 6-minute walk test (6MWT) can improve risk prediction in people with stable coronary disease, according to a new study published in the Archives of Internal Medicine. The 6MWT may also be cost-effective and — and may help physicians motivate their patients to exercise, suggest the authors.

Alexis Beatty and colleagues performed a 6MWT and a treadmill exercise test in 556 people with stable coronary heart disease. After a median follow-up of 8 years, cardiovascular (CV) events had occurred in 39.2% of the study participants.

Compared with people in the highest quartile of walking distance (544-837 m), people in the lowest quartile (87-419 m) had four times the risk for a CV event during follow-up.

  •  Unadjusted hazard ratio: 4.29, CI 2.83-6.53, p<0.001

After adjustment for other factors, each 104-m decrease in walking distance (1 standard deviation) was associated with a 30% increase in CV events (HR 1.30,CI 1.10-1.53). The 6MWT was similar to the treadmill exercise test in predicting CV events.

The authors write that treadmill testing is still preferable for evaluating patients with suspected ischemia, but they note a number of advantages to the 6MWT in stable patients:

The 6MWT can be conducted with little equipment other than a hallway marked for distance and a stopwatch. Due to the self-paced nature of the test, adverse events of chest pain, dyspnea, or musculoskeletal pain are usually mild; serious adverse events have not been described. Furthermore, the 6MWT is less expensive than treadmill exercise testing, especially if stress testing is bundled with imaging that may be unnecessary.

Furthermore, the 6MWT can be used to motivate patients to exercise:

Despite evidence demonstrating the efficacy of exercise-based rehabilitation in patients with CHD for reducing mortality, most patients do not participate in cardiac rehabilitation or achieve recommended levels of physical activity. There is a need for improved strategies to identify patients at the greatest risk of cardiovascular events and to motivate patients and physicians to address physical activity as a modifiable risk factor. Repeated measurement of the 6MWT could be used as a simple office-based tool to monitor exercise capacity and motivate patients to achieve appropriate levels of physical activity. Although we demonstrated that the 6MWT can predict cardiovascular events in stable CHD, its use for improving prognosis merits further study.

In an accompanying comment, David Nash agrees with the investigators and recommends “that physicians interested in improving their patients’ level of fitness use the 6MWT as a means of getting the patient started on regular exercise. Once the patients become familiar with the ease and safety of the 6MWT, they can be encouraged to repeat the 6MWT more frequently, even on a daily basis. It is then possible to lengthen the walk at appropriate intervals.”

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