Abstract Details

Title A Concisely Recorded Ambulatory Assessment for Enhancing Real-World Outcomes Research in Duchenne Muscular Dystrophy: Development and Validation

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) P13 - Poster Session 13 (8:00 AM-9:00 AM)

Poster/Presentation
Number 11-003

Background The North Star Ambulatory Assessment (NSAA), which consists of 17 functional items, is foundational for ambulatory DMD care and is regularly conducted per care guidelines and recorded in medical records throughout the United Kingdom, Europe and elsewhere. At too many centers and practices, however, recording of standardized ambulatory assessments in DMD medical records is limited or inconsistent, which hinders retrospective learning from real-word data in this rare, progressive and life-limiting disease.

Objective To evaluate whether consistently recording a concise subset of ambulatory assessments, conducted as part of a complete assessment per care guidelines, could accurately quantify real-world disease progression for Duchenne Muscular Dystrophy (DMD) research.

Design/Methods Drawing on data from over 1,800 complete NSAA assessments among 320 patients in the North Star Clinical Network database, we applied machine learning (penalized regression) to identify item subsets that best predicted total score. Predictions were evaluated in a held-out sample with the standard error of measurement (SEM) of the NSAA total score (previously estimated at 2.7 units) serving as a benchmark for sufficient accuracy.

Results A subset of six NSAA items (hop, jump, rise, climb, walk, stand) predicted total score in validation data with correlation 0.97 and prediction error 1.8 units, less than the SEM. Prediction errors remained consistently below the SEM when stratified by age groups and by NSAA total score level. These six items accord with key markers of progression in recent DMD disease models.

Conclusions The full NSAA should be conducted by trained assessors, consistent with care guidelines, so that disease management is not divorced from measurement. When entry of all NSAA items into the medical record is not possible, consistently prioritizing entry of the six items identified here would significantly broaden the foundation for real-world outcomes research in ambulatory DMD.

Authors/Disclosures
PRESENTER	No disclosure on file
	No disclosure on file
	No disclosure on file
Chiara Marini-Bettolo (Newcastle University)	Chiara Marini-Bettolo has nothing to disclose.
Chiara Marini-Bettolo (Newcastle University)	Chiara Marini-Bettolo has nothing to disclose.
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
Francesco Muntoni, MD (UCL Institute of Child Health)	Dr. Muntoni has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Sarepta. Dr. Muntoni has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Pfizer. Dr. Muntoni has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Sarepta. Dr. Muntoni has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Pfizer. Dr. Muntoni has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Biogen. Dr. Muntoni has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Avexis. Dr. Muntoni has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Roche. The institution of Dr. Muntoni has received research support from European Commission. The institution of Dr. Muntoni has received research support from Medical Research Council. The institution of Dr. Muntoni has received research support from Biogen. The institution of Dr. Muntoni has received research support from Muscular Dystrophy UK. The institution of Dr. Muntoni has received research support from MDA USA. The institution of Dr. Muntoni has received research support from Sarepta. The institution of Dr. Muntoni has received research support from Association Francoise Myopathies. Dr. Muntoni has received personal compensation in the range of $0-$499 for serving as a Clinical expert with UK NICE Committee.