Table 3.
Respiratory interventions, motor function, surgeries and hospitalizations among living individuals with SMA types I, II, and III*
| Characteristics | 2018 Survey (living individuals) | 2017 Survey (living individuals) | ||||
| Type I | Type II | Type III | Type I | Type II | Type III | |
| (n = 157) | (n = 275) | (n = 171) | (n = 105) | (n = 265) | (n = 187) | |
| Current use of respiratory intervention, n (%) | ||||||
| Yes | 144 (91.7) | 190 (69.1) | 34 (19.9) | 97 (92.4) | 181 (68.3) | 36 (19.3) |
| No | 10 (6.4) | 70 (25.5) | 126 (73.7) | 7 (6.7) | 74 (27.9) | 135 (72.2) |
| Unknown/missing | 3 (1.9) | 15 (5.5) | 11 (6.4) | 1 (1.0) | 10 (3.8) | 16 (8.6) |
| Type of current respiratory interventions, n (%) | ||||||
| Oxygen | 21 (13.4) | 24 (8.8) | 1 (0.6) | 24 (22.9) | 24 (9.1) | 1 (0.5) |
| BiPAP | 74 (47.1) | 95 (34.7) | 12 (7.0) | 45 (42.9) | 97 (36.6) | 13 (7.0) |
| CPAP | 1 (0.6) | 7 (2.6) | 8 (4.7) | 12 (1.0) | 4 (1.5) | 9 (4.8) |
| Cough assist | 156 (69.4) | 156 (56.9) | 15 (8.8) | 77 (73.3) | 142 (53.6) | 18 (9.6) |
| Ventilator | 58 (36.9) | 18 (6.6) | 0 | 42 (40.0) | 24 (9.1) | 0 |
| Tracheostomy | 48 (30.6) | 10 (3.7) | 0 | 39 (37.1) | 9 (3.4) | 0 |
| Current motor function(s) at time of survey† | ||||||
| Head control | 82/148 (55.4) | 237/270 (87.8) | 159/169 (94.1) | 39/96 (40.6) | 216/243 (88.9) | 162/175 (92.6) |
| Maintains seated position supported | 53/148 (35.8) | 204/270 (75.6) | 155/169 (91.7) | 28/96 (29.2) | 184/243 (75.7) | 158/175 (90.3) |
| Maintains seated position unsupported | 32/144 (22.2) | 127/270 (47.0) | 148/169 (87.6) | 11/93 (11.8) | 127/242 (52.5) | 145/175 (82.9) |
| Stands with support | 8/141 (5.7) | 30/270 (11.1) | 111/169 (65.7) | 5/91 (5.5) | 28/242 (11.6) | 85/175 (48.6) |
| Walks with support | 4/131 (3.1) | 16/270 (5.9) | 93/169 (55.0) | 2/89 (2.2) | 14/242 (5.8) | 69/175 (39.4) |
| Walks independently | 3/125 (2.4) | 4/270 (1.5) | 76/169 (45.0) | 0 | 6/241 (2.5) | 53/175 (30.3) |
| Surgeries ever had related to SMA, n (%)‡ | ||||||
| Yes | 132 (83.0) | 178 (64.7) | 41 (23.8) | 101 (92.7) | 227 (85.3) | 82 (43.9) |
| No | 19 (12.0) | 83 (30.2) | 102 (59.3) | 8 (7.3) | 39 (14.7) | 105 (56.2) |
| Unknown/missing | 8 (5.0) | 14 (5.1) | 29 (16.9) | 0 | 0 | 0 |
| Type of SMA-related surgeries, if ever SMA-related surgery¶ | ||||||
| Scoliosis | 31 (23.5) | 124 (69.7) | 26 (63.4) | 31 (31.6) | 133 (79.2) | 35 (64.8) |
| Orthopedic | 10 (7.6) | 43 (24.2) | 7 (17.1) | 10 (10.2) | 48 (28.6) | 14 (25.9) |
| Gastrointestinal | 127 (96.2) | 85 (47.8) | 3 (7.3) | 94 (95.9) | 64 (38.1) | 2 (3.7) |
| Otolaryngology/oral | 27 (20.5) | 45 (25.3) | 10 (24.4) | 11 (11.2) | 31 (18.5) | 9 (16.7) |
| Respiratory | 57 (43.2) | 14 (7.9) | 0 | 39 (39.8) | 13 (7.7) | 0 |
| Any hospitalizations in past 12 months, n (%)§ | ||||||
| Yes | 82 (51.6) | 98 (35.6) | 24 (14.0) | 49 (46.79) | 72 (27.2) | 12 (6.4) |
| No | 63 (39.6) | 153 (55.6) | 122 (71.4) | 45 (42.9) | 155 (58.5) | 151 (80.8) |
| Unknown/missing | 14 (8.8) | 24 (8.7) | 25 (14.6) | 11 (10.5) | 38 (14.3) | 24 (12.8) |
| Reasons for hospitalization in past 12 months | – | – | – | |||
| Respiratory distress | 47 (29.6) | 47 (17.1) | 3 (1.7) | |||
| Pneumonia | 34 (21.4) | 44 (16.0) | 3 (1.7) | |||
| Infection (other than pneumonia) | 21 (13.2) | 35 (12.7) | 5 (2.9) | |||
| Failure to thrive | 6 (3.8) | 1 (0.4) | 0 | |||
| Dehydration | 11 (6.9) | 19 (6.9) | 0 | |||
| Feeding tube problems | 7 (4.4) | 4 (1.5) | 0 | |||
| Abdominal | 1 (0.6) | 8 (2.9) | 2 (1.2) | |||
| Trauma, fracture or external injury | 2 (1.3) | 2 (0.7) | 4 (2.3) | |||
| Headache | 2 (1.3) | 2 (0.7) | 2 (1.2) | |||
| Surgery | 19 (12.0) | 25 (9.1) | 3 (1.7) | |||
| Laminectomy | 1 (0.6) | 1 (0.4) | 1 (0.6) | |||
BiPAP, bilevel positive airway pressure; CPAP, continuous positive airway pressure; VEPTR, vertical expandable prosthetic titanium rib; SMA, spinal muscular atrophy; CDC, Centers for Disease Control and Prevention. *Questions were not asked of caregivers of deceased individuals. †Respondents selected a single response reflecting current maximum motor function; they did not indicate all current motor function(s). To derive an indicator of whether the affected individual had each motor function at the time of survey, the response options were treated as a continuum, encompassing head control maintaining seated position (with or without support), stands with support, walks with support, and walks independently. If “none of the above” was selected, the affected individual was assumed to not have current head control (the lowest function on the continuum). Given the heterogeneous age range of patients and the fact that some had not yet reached the age at which they would be expected to achieve various motor milestone (based on CDC guidelines [43]), denominators were adjusted to accurately determine proportions currently able to perform each motor function. The age cut-offs for each motor function were as follows: 4 months for head control, 4 months of maintains seated position supported, 7 months for maintains seated position unsupported, 8 months for stands with support, 11 months for walks with support, 15 months for walks independently. Patients who were missing data for this question and those who had not yet reached the milestone and where younger than the CDC age cut-offs, were removed from the denominator. Denominators are given for each milestone by type in the table. ‡Created variable –“Yes” coded based on “yes” to any of the following: spinal fusion, spinal rods, VEPTR, MAGEC® rods, hip surgery, joint contractures, ankle or foot surgery, Nissen fundoplication, g-tube placement, gastrostomy tonsillectomy, dental surgery, and ear tube placement, or tracheostomy. “No” coded based on endorsement of an item indicating the affected individual never had an SMA-related surgery. ¶Surgical procedures related to SMA included scoliosis surgery (spinal fusion, spinal rods, VEPTR, and MAGEC® rods), orthopedic surgery (hip surgery, joint contractures, and ankle or foot surgery), gastrointestinal surgery (Nissen fundoplication, g-tube placement, and gastrostomy), otolaryngology/oral surgery (tonsillectomy, dental surgery, and ear tube placement), and respiratory surgery (tracheostomy). §In 2018 survey, “No” was for either answering “0” for number of times they were hospitalized in the last 12 months or selecting “I was not hospitalized in the last 12 months” when asked for the reason for hospitalization.