Two 6-Minute Walk Tests Recommended for Suspected Pulmonary Hypertension

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In the initial assessment, more than half of the study participants were able to walk farther in the second 6MWT than in the first.
In the initial assessment, more than half of the study participants were able to walk farther in the second 6MWT than in the first.

Patients with suspected pulmonary hypertension (PH) should undergo two 6-minute walk tests (6MWTs) to minimize the "learning effect" and improve the accuracy of exercise capacity measurements, according to retrospective findings published in Chronic Respiratory Disease.

Investigators compared walking distances in patients with PH who performed two 6MWTs to determine whether a "learning effect" existed and whether a second 6MWT was associated with improved exercise capacity. For the purposes of this study, a learning effect consisted of patient motivation, confidence, anxiety, familiarity with the walking track, and improved coordination.

 

At the initial assessment, a total of 214 participants with suspected PH underwent two 6MWTs (6MWT1 and 6MWT2), and at 6 months, 71 participants completed two 6MWTs (6MWT3 and 6MWT4). None of the patients had a prior history of completing these tests before entering the study.

Participants were able to walk farther in the second 6MWT compared with the first 6MWT in the initial assessment (mean difference, 19 m; 95% CI, 14-24 m, P <.001). More than half of participants in the initial assessment were able to walk farther in 6MWT2 vs 6MWT1.

In addition, a second 6MWT4 at 6-month follow-up was associated with a significantly greater distance traveled than the first 6MWT3 (mean difference, 19 m; 95% CI, 10-27; P <.001). Conversely, no significantly different changes occurred in walking distance among participants who walked <300 minutes during the initial assessment (mean difference, 9 m; 95% CI, −5 to 22 m; P =.208).

Considering this study was retrospective and evaluated only patients who were referred to a single center, the findings are limited to this specific patient population.

In this study and in real-world clinical practice, a second 6MWT is "more likely to reflect the participant's true functional exercise capacity by taking into account the learning effect and as such, would be a more valid comparison with subsequent 6MWTs used for ongoing monitoring."

Reference

Spencer L, Zafiropoulos B, Denniss W, Fowler D, Alison J, Celermajer D . Is there a learning effect when the 6-minute walk test is repeated in people with suspected pulmonary hypertension [published online January 23, 2018]? Chron Respir Dis. doi:10.1177/1479972317752762

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