Going places: Does the two-minute walk test predict the six-minute walk test in lower extremity amputees?

Abstract

Assessing a patient's ability to walk the distance required for community ambulation (at least 300 m) is important in amputee rehabilitation. During the 2-min walk test, most amputees cannot walk 300 m. Thus, the 6-min walk test may be preferred, but it has not been fully validated in this population. This study examined the convergent and discriminative validity of the 6-min walk test and assessed whether the 2-min test could predict the results of the 6-min test. A total of 86 patients with unilateral or bilateral amputations at the Syme, transtibial, knee disarticulation or transfemoral level completed the 6-min walk test, 2-min walk test, Timed Up and Go test, Locomotor Capabilities Index version 5, Houghton Scale of Prosthetic Use, and Activity-Specific Balance Confidence scale. The 6-min walk test correlated with the other tests (R = 0.57-0.95), demonstrating convergent validity. It demonstrated discriminative validity with respect to age, aetiology of amputation, and K-level (p < 0.0001). The 2-min walk test was highly predictive of the 6-min walk test distance (R2 = 0.91). The 6-min walk test is a valid measure of amputee ambulation. However, the results suggest that it may not be necessary, since the 2-min walk test strongly predicts the 6-min walk test. Clinicians could therefore save time by using the shorter test.