Fig. 2

Distance walked in the 6-min walk test. a Baseline distance walked plotted against reference data [29] by age at assessment (n = 38). b Absolute change from baseline^a in distance walked in patients with data available after 1, 2 or 3 years of treatment with idursulfase. c Percentage change from baseline in distance walked in patients with data available after 1, 2 or 3 years of treatment with idursulfase. Box plots illustrate the 25th, 50th (median) and 75th percentiles (boxes) and the 10th and 90th percentiles (whiskers). ^aThe baseline measurement was defined as the last recorded measurement in the 12 months preceding the start of idursulfase treatment. A post-baseline measurement was defined as the value recorded closest to the 1st, 2nd or 3rd-year anniversary of the baseline measurement, within 6 months either side of the anniversary date. If there were two values within equal times of the evaluation visit, the first value was used