Reference curves of motor function outcomes in young steroid-naïve males with Duchenne muscular dystrophy

Abstract

Aim: To investigate functional motor performance in a large cohort of young ster-oid-naïve males with Duchenne muscular dystrophy (DMD) and typically develop-ing males, and to develop specific reference curves for both groups. Also, to describeassociations between anthropometric values and functional motor outcomes.Method: Cross-sectional data of 196 steroid-naïve males with DMD aged 4 to 8 yearsand 497 typically developing males aged 2 years 6 months to 8 years were included.Both groups were evaluated with the time to rise from the floor test, 10-metre walk/run test, 6-minute walk test, and North Star Ambulatory Assessment. Referencecurves with centiles 5%, 10%, 25%, 50%, 75%, 90%, and 95% were estimated usingquantile regression.Results: Males with DMD scored significantly worse on all functional motor out-comes than age-matched typically developing males (p < 0.001): 89% to 95% of themales with DMD scored below the 5th centile of the typically developing males. Noor weak correlations exist between anthropometric values and functional motoroutcomes.Interpretation: The estimated reference curves can support consultation with fami-lies of young males with DMD and can support the evaluation of treatment for reach-ing motor skills and functional motor outcomes compared with typically developingmales.This original article is commented on by Baranello on pages 557–558 of this issue.