The 6-minute walk test and other endpoints in Duchenne muscular dystrophy: longitudinal natural history observations over 48 weeks from a multicenter study.
Bottom Line: Baseline age (≥7 years), 6MWD, and selected TFT performance are strong predictors of decline in ambulation (Δ6MWD) and time to 10% worsening in 6MWD.A baseline 6MWD of <350 meters was associated with greater functional decline, and loss of ambulation was only seen in those with baseline 6MWD <325 meters.Only 1 of 42 (2.3%) subjects able to stand from supine lost ambulation.
Affiliation: Department of Physical Medicine and Rehabilitation, University of California Davis School of Medicine, Davis, California, 95817, USA.Show MeSH
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Mentions: To assist clinical investigators with clinical trial design, we have provided the mean and SD from baseline to week 48 at 6-week intervals and the corresponding mean and SD change from baseline for both 6MWD and percent predicted 6MWD for all subjects (Table 3), steroid-treated patients (Table 4), and steroid-naive patients <7 years of age (Table 5). As seen in Figure 6a and b, there appears to have been be a progressive decline over 6-week intervals in mean 6MWD and predicted 6MWD. The effect of age on the progression of endpoints is shown for mean 6MWD (Fig. 6c) and mean percent predicted 6MWD (Fig. 6d) in steroid-treated DMD patients. The effect of long-term administration of glucocorticoid (≥6 months of stable dosing) on changes in ambulatory function (assessed as change in 6MWD at 6-week intervals over 48 weeks) is shown for <7-year-olds (Fig. 7a) and ≥7-year-olds (Fig. 7b). Although results are not statistically significant due to small numbers, the effect of long-term steroids on ambulatory function appears to have been greater for patients <7 years of age (Fig. 7a). In contrast, this long-term steroid effect was not observed in patients ≥7 years of age. Patients ≥7 years of age either on steroids (n = 34) or steroid-naive (n = 9) exhibited similar declines in 6MWD over 48 weeks (Fig. 7b).
Affiliation: Department of Physical Medicine and Rehabilitation, University of California Davis School of Medicine, Davis, California, 95817, USA.