Agreements and Discrepancies between the  Estimated Walking Distance, Nongraded and Graded Treadmill Testing, and Outside Walking in XXXX with @entity613 .

@entity1 @entity23756 @entity613 @entity4511
BACKGROUND: Disease severity in @entity1 with @entity613 ( @entity613 ) is often assessed using walking distances and treadmill tests. The aim of this study was to determine the agreement between walking distance as estimated by the @entity1 , as measured during outside walking, and as determined using a nongraded treadmill protocol (NGTP), and an incremental graded ( @entity4511 ) treadmill protocol ( @entity23756 ). METHODS: In this prospective observational study, 30 @entity1 with @entity613 estimated their maximal walking distance (MWD) and completed a "Walking Impairment Questionnaire" (WIQ). Outside walking was determined using a measuring wheel and a @entity23756 controlled device. Primary outcomes were differences in MWD and variability (coefficient of variation, COV). Secondary outcomes were results of WIQ and differences in walking speed. RESULTS: Estimated walking distance was significantly higher than MWD as objectively measured during outside walking (400 m vs. 309 m, respectively, P  =  0.02). A substantial variability (COV  =  55%) was found between both parameters. A small 35-m MWD difference between outside walking and @entity23756 was found with a substantial scatter (COV  =  42%). In contrast, a much larger 122-m MWD difference was present between outside walking and NGTP (COV = 89%). @entity1 walked significantly faster in the open air than on treadmills (median outside walking speed  =  3.8  km/hr, @entity23756  =  3.2  km/hr, NGTP  =  2.8  km/hr; P  <  0.001). CONCLUSIONS: An incremental graded ( @entity4511 ) treadmill protocol demonstrated the best agreement to outside walking. Discrepancies between treadmill tests and outside walking may be explained by a difference in walking speed. A single determination of a walking distance is a poor reflection of true walking capacity.
