The 6‐minute walk test as a new outcome measure in Duchenne muscular dystrophy

Walking abnormalities are prominent in Duchenne muscular dystrophy (DMD). We modified the 6‐minute walk test (6MWT) for use as an outcome measure in patients with DMD and evaluated its performance in 21 ambulatory boys with DMD and 34 healthy boys, ages 4 to 12 years. Boys with DMD were tested twice, ∼1 week apart; controls were tested once. The groups had similar age, height, and weight. All tests were completed. Boys who fell recovered rapidly from falls without injury. Mean ± SD [range] 6‐minute walk distance (6MWD) was lower in boys with DMD than in controls (366 ± 83 [125–481] m vs. 621 ± 68 [479–754] m; P < 0.0001; unpaired t‐test). Test‐retest correlation for boys with DMD was high (r = 0.91). Stride length (R2 = 0.89; P < 0.0001) was the major determinant of 6MWD for both boys with DMD and controls. A modified 6MWT is feasible and safe, documents disease‐related limitations on ambulation, is reproducible, and offers a new outcome measure for DMD natural history and therapeutic trials. Muscle Nerve, 2010