Table 1. Clinical data of SMA and Control Subjects.
| SMA Type I | SMA Type II | SMA Type III | Control | p-value* | p-value* | |
| N = 17 | N = 49 | N = 42 | N = 22 | I vs IIvs III | SMA vs Control | |
| Age | ||||||
| mean (SD) | 5.70 (3.54), | 6.55 (3.40), | 7.51 (3.11), | 6.95 (3.29), | 0.14 | 0.84 |
| median [range] | 4.03 [2.4–12.7] | 6.49 [2.2–13.0] | 7.42 [2.4–13.0] | 6.02 [2.2–13.0] | ||
| Sex, n (%) | 0.73 | 0.64 | ||||
| Male | 10 (59%) | 26 (53%) | 20 (48%) | 10 (46%) | ||
| 2–5 years old | 6 | 15 | 7 | 5 | ||
| 6–12 years old | 4 | 11 | 13 | 5 | ||
| Female | 7 (41%) | 23 (47%) | 22 (52%) | 12 (54%) | ||
| 2–5 years old | 5 | 9 | 8 | 6 | ||
| 6–12 years old | 2 | 14 | 14 | 6 | ||
| MHFMS, | ||||||
| mean (SD) | 0 (0) | 14.02 (10.5) | 34.1 (10.0) | 39.8 (0.7) | <0.001 | <0.001 |
| median [range] | 0 [0–0] | 11 [0–36] | 40 [2]–[40] | 40 [37]–[40] | ||
| Current Motor Function, n (%) | <0.001 | <0.001 | ||||
| Sit | 0 (0%) | 42 (85.7%) | 41 (97.6%) | 22 (100%) | ||
| Walk | 0 (0%) | 0 (0%) | 32 (76.2%) | 22 (100%) | ||
| Feeding Method | <0.001 | 0.07 | ||||
| solid food | 1 (5.9%) | 44 (89.8%) | 41 (97.6%) | 22 (100%) | ||
| modified oral intake | 2 (11.8%) | 2 (4.1%) | 1 (2.4%) | 0 (0%) | ||
| G-tube fed | 14 (82.4%) | 3 (6.1%) | 0 (0%) | 0 (0%) | ||
| BMI z-Score | 0.04 | 0.17 | ||||
| mean (SD) | −2.54 (3.98) | −0.90 (4.13) | −0.09 (1.65) | 0.16 (1.02) | ||
| median [range] | −1.34 [−9.7 to 3.4] | −0.12 [−19.7 to 3.6] | −0.05 [−4.2 to 3.2] | 0.34 [−1.8 to 1.9] | ||
| FVC% Predicted | <0.001 | 0.08 | ||||
| mean (SD) | N/A | 70.04 (30.10) | 104.1 (18.9) | 103.3 (10.6) | ||
| median [range] | N/A | 66.5 [26–135] | 105 [61–153] | 103 [87–125] | ||
| 10 meter walk | ||||||
| mean (SD) | NA | NA | 10.1 (6.1) | 3.5 (1.5) | NA | <0.001 |
| median [range] | NA | NA | 9 [3.4–34] | 3 [2.2–8.8] | ||
| Age of Disease Onset | NA | <0.001 | NA | |||
| 0–6 months | 17 (100%) | 10 (20.4%) | 1 (2.4%) | |||
| 7–17 months | 0 (0%) | 35 (71.4%) | 20 (47.6%) | |||
| 18+months | 0 (0%) | 4 (8.2%) | 21 (50.0%) | |||
| Respiratory support | <0.001 | 0.001 | ||||
| BIPAP or tracheostomy | 15 (88%) | 8 (16%) | 0 (0%) | 0 (0%) | ||
| Cough assist | 1 (6%) | 14 (29%) | 1 (3%) | 0 (0%) |
ANOVA for continuous variables; Fisher exact test for categorical variables.
There were no significant differences in age or gender across the recruitment cohorts. A key goal of this study was to minimize the confounding correlation between present age and functional status. This goal was largely achieved, both overall and within SMA groups Type II and III, and to a partial extent, SMA Type I through a competitive recruitment plan managed through the data coordinating center at the New England Research Institutes (NERI). The Modified Hammersmith Motor Function Scale differentiated between SMA subjects and controls and between Type I, II and III subjects, as did respiratory support, reflecting current level of function. FVC and the nutritional assessment score significantly distinguished between SMA type; however, BMI proved to be far less discriminatory.