Natural history of timed rise from floor in young individuals with Duchenne muscular dystrophy: A single-center retrospective study

Abstract

Introduction

Motor function in patients with Duchenne muscular dystrophy (DMD) is commonly evaluated using the 6-min walk test, North Star Ambulatory Assessment, and timed function tests. However, few reports have examined the progression of timed rise from floor (TRF) in patients with DMD undergoing steroid therapy in Japan. We investigated the natural history of TRF in patients with DMD treated in Japan.

Methods

We retrospectively assessed TRF by age group based on data collected from October 2010 to August 2023. We used Kaplan–Meier curves to analyze the loss of the ability to rise from the floor. Additionally, receiver operating characteristic analysis was performed to predict the loss of the ability to stand up after 1 year.

Results

In total, 165 males with DMD were enrolled. The median TRF peaked at 6 years of age and deteriorated thereafter. The median age of the loss of the ability to rise from the floor was 11.9 years (95 % confidence interval = 10.6–13.2). Using a TRF cutoff of 6.2 s, the sensitivity, specificity, and area under the curve for predicting loss of the ability to rise from the floor in 1 year were 71 %, 90 %, and 0.914, respectively.

Conclusion

This study provided insights into the deterioration of TRF in patients with DMD receiving steroid treatment in Japan. As a simple and easily measurable parameter, TRF is a useful tool for predicting the progression of motor function.