Concurrent validity of the 2-and 6-minute walk test in knee osteoarthritis

Abstract

Background: The 6-Minute Walk Test (6MWT) is frequently used for the assessment of walking distances in several conditions, as knee osteoarthritis, but it can be both time-consuming for the researcher or clinician, and exhausting of painful for the subject suffering from this condition. The objective of our study was to analyze the concurrent validity of the 2-Minute Walk Test (2MWT) for patients with knee osteoarthritis compared to the 6-Minute Walk Test (6MWT).

Methods: Cross-sectional validation study. Scores from the 6MWT of 42 ambulatory patients affected by knee osteoarthritis were compared to those from the shorter 2MWT. An initial correlation test was used to assess correlation between both measures, and a subsequent univariate regression analysis was performed with the aim of comparing the estimated outcomes of the 6MWT versus the actual 6MWT.

Results: The scores from the 2MWT and 6MWT showed excellent correlation (Pearson's correlation coefficient r = 0.976; p-value < 0.001); the predictive equation based on the scores from the 2MWT (R² = 0.952, p-value < 0.001) estimates the 6MWT scores with a relative error of 3.23%.

Conclusions: The 2MWT may be a practical assessment tool in replacement for the 6MWT in clinical assessment due to its low burden on patients and as a means of improving efficiency in a timely manner.

Keywords: 2-Minute Walk Test; 6-Minute Walk Test; Clinical Assessment; Clinimetrics; Knee Injuries; Knee Osteoarthritis.