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: The 1-year natural history of changes in 6MWD and age- and height-based percent predicted 6MWD is shown in Figure 4a and b. Although differences between absolute values and percent predicted are obviously subtle it should be noted that a 6MWD of 450 m is approximately 80% predicted for a 6-year-old and 65% predicted for a 13-year-old. As shown previously,5,6 age and baseline walking ability are 2 important variables that determine decline in ambulation as measured by 6MWT; there is a tendency for the 6MWD to improve or be stable over the first 7 years of age,5,6,8,9 and patients who have lower initial 6MWD values and percent predicted 6MWD tend to show greater declines over the course of 48 weeks. Patients ≥7 years of age may show stable function or even improving function over 48 weeks, but they are almost always those with higher levels of baseline function (6MWD >350 m or percent predicted 6MWD >60%). Conversely, patients with baseline 6MWD <350 m demonstrate a greater decline in 6MWD over the 48-week evaluation period (Fig. 5).
Affiliation: Department of Physical Medicine and Rehabilitation, University of California Davis School of Medicine, Davis, California, 95817, USA.