Table 1.A.

Baseline Demographics for Cohort ^*

	All DMD N=85
Characteristics	N = 85
Average age, y	14.9 (3.5–37.5)a
Median Age at loss of ambulation, y	10 (4–14)a
% of subjects still ambulatory	32.6
BSA, m2	1.2 [0.9,1.5]b
BMI, kg/m2	20.1 [16.5,25.9]b
BMI Z score	1.1 [0.2,1.9]b
Fractional Shortening, %	34 [31,37.1]b
CMR Ejection Fraction, %	57 [50.0,60.9]b
Left ventricular mass, grams	65.6 [51.5,82.5]b
LVIDd, mm	40.0 [37,44]b
LVIDs, mm	26 [24,30]b
Corticosteroid use, %	52

^*Based on echocardiographic measurements unless CMR labeled

^aexpressed as range

^bexpressed in median [IQR]