Fig. 5

Modeling of distance walked in 6MWT over time following IV idursulfase treatment using data from patients who received ERT for 5 years or more. (a) Change in predicted means and 95% CIs by age at ERT start (colored lines) and individual patient values (gray lines) from pre-ERT up to 8 years after IV idursulfase start in the main analysis population (patients with data available for at least two time points in total and at least one post-ERT time point; n = 76). (b) Predicted means by age at ERT start at pre-ERT and 8 years post-ERT in the main analysis population and the internal validation population (patients with data available at five or more time points). Patients who had cognitive impairment at any time and patients who needed assistance to perform the assessment were excluded from the model. Patients aged under 5 years at the time of assessment were also excluded owing to the unreliability of these assessments in children aged under 5 years [17]; pre-ERT values are therefore labeled ‘not applicable’ for patients aged under 5 years at ERT start. For reference, the mean (95% CI) distance walked in a previous 6MWT analysis of a population of healthy male individuals increased from 536.5 m (494.1, 578.9) in boys aged 3–5 years to 577.8 m (564.0, 591.6), 672.8 m (656.6, 689.2), 697.8 m (681.2, 714.4) and 725.8 m (709.3, 742.4) in boys aged 6–8 years, 9–11 years and 12–15 years and in adolescent males aged ≥ 16 years, respectively [33]. Abbreviations: 6MWT, 6-min walk test; CI, confidence interval; ERT, enzyme replacement therapy; IV, intravenous; NA, not applicable; ND, not determined; SE, standard error