muscular dystrophy prognosis

[Elisha Li]

Hi! Do you have a good reference article for using outcome measures to determine prognosis for those with muscular dystrophies? I remember in the PCS Prep course that there was a TUG cutoff that helped predict loss of ambulation. Are there articles were I can find similar values for other OMs?

[Jessica Lewis]

The 6-Minute Walk Test is the strongest outcome measure for DMD (currently). A recent systematic review goes over a few outcome measures with some cut-offs (Landfeldt, 2024).
Here are the ones I know best:
6 Minute Walk Test
• <350 meters is usually the threshold; boys tend to lose ambulation within 24 months when they are below this point
• Rapid decline of >30 meters/year also predicts transition toward loss of ambulation
• Landfeldt E, Alemán A, Abner S, et al. Predictors of Loss of Ambulation in Duchenne Muscular Dystrophy: A Systematic Review and Meta-Analysis. J Neuromuscul Dis. 2024;11(3):579-612. doi:10.3233/JND-230220.
North Star Ambulatory Assessment
• Lower total scores (usually <20-22) are associated with faster decline
• Inability to perform key items (run, jump, rise from floor) strongly predicts near term loss of ambulation
• Landfeldt article
• Mazzone ES, Pane M, Sormani MP, et al. 24 month longitudinal data in ambulant boys with Duchenne muscular dystrophy. PLoS One. 2013;8(1):e52512. doi:10.1371/journal.pone.0052512
Timed Function Tests often decline before 6MWT drops dramatically
• Time to Rise from Floor, Time to Climb 4 Stairs, 10-Meter Walk/Run Time
• Rise from floor >6-8 seconds predicts decline, loss of ability to rise independently strongly predicts loss of ambulation within one year
• Mazzone ES, Coratti G, Sormani MP, et al. Timed Rise from Floor as a Predictor of Disease Progression in Duchenne Muscular Dystrophy: An Observational Study. PLoS One. 2016;11(3):e0151445. Published 2016 Mar 16. doi:10.1371/journal.pone.0151445

[Emily Brodbeck]

What is the cutoff for the TUG for the DMD population?

[Helen Carey]

Hi Emily,
I was not able to find any data on the TUG for DMD. The timed function tests that Jessica mentions above are what we have found in the literature (Time to Rise from Floor, Time to Climb 4 Stairs, 10-Meter Walk/Run Time). I included this reference in the NMD study guide, which might also be helpful:
Birnkrant DJ, Bushby K, Bann CM, Apkon SD, Blackwell A, Brumbaugh D, Case LE, Clemens PR, Hadjiyannakis S, Pandya S, Street N, Tomezsko J, Wagner KR, Ward LM, Weber DR; DMD Care Considerations Working Group. Diagnosis and management of Duchenne muscular dystrophy, part 1: diagnosis, and neuromuscular, rehabilitation, endocrine, and gastrointestinal and nutritional management. Lancet Neurol. 2018 Mar;17(3):251-267. doi: 10.1016/S1474-4422(18)30024-3. Epub 2018 Feb 3. Erratum in: Lancet Neurol. 2018 Jun;17(6):495. doi: 10.1016/S1474-4422(18)30125-X. PMID: 29395989; PMCID: PMC5869704.

Hope this helps!
Helen

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