Table 1.
Baseline demographic and clinical characteristics of the patient sample
| Total sample (n = 150) | Lower total score (i.e., worsened ability) at follow-up (n = 65) |
Same total score at follow-up (n = 49) | Higher total score (i.e., improved ability) at follow-up (n = 36) |
p value† | |
|---|---|---|---|---|---|
| Age, mean (SD) years | 45 (14) | 50 (12) | 39 (16) | 46 (11) | 0.001 |
| Sex, female | 78 (52%) | 38 (58%) | 24 (49%) | 16 (44%) | 0.352 |
| Age at first symptoms, mean (SD) yearsa | 26 (17) | 28 (18) | 23 (17) | 27 (16) | 0.343 |
| Disease duration, mean (SD) yearb | 20 (12) | 22 (13) | 16 (12) | 20 (11) | 0.090 |
| Type of DM1c | |||||
| Congenital | 8 (5%) | 2 (3%) | 5 (11%) | 1 (3%) | 0.141 |
| Classical | 101 (70%) | 45 (70%) | 29 (64%) | 27 (75%) | 0.583 |
| Late onset | 36 (25%) | 17 (27%) | 11 (24%) | 8 (22%) | 0.888 |
| Part-time wheelchair dependency | 22 (15%) | 10 (15%) | 4 (8%) | 8 (22%) | 0.190 |
| 6-minute walk test | |||||
| Baseline result, mean (SD) metersd | 422 (152) | 407 (129) | 489 (155) | 375 (137) | 0.002 |
| Follow-up result, mean (SD) meterse | 404 (157) | 356 (149) | 491 (151) | 368 (132) | < 0.001 |
| Δ (follow-up—baseline result)e | − 30 (71) | − 52 (82) | − 14 (57) | − 14 (56) | 0.015 |
| Muscular impairment rating scale (MIRS) score | |||||
| I | 19 (13%) | 7 (11%) | 9 (18%) | 3 (8%) | 0.323 |
| II | 40 (27%) | 15 (23%) | 20 (41%) | 5 (14%) | 0.015 |
| III | 30 (20%) | 15 (23%) | 8 (16%) | 7 (19%) | 0.669 |
| IV | 47 (31%) | 22 (34%) | 9 (18%) | 16 (44%) | 0.032 |
| V | 14 (9%) | 6 (9%) | 3 (6%) | 5 (14%) | 0.477 |
| Education, mean (SD) years completedd | 15 (3) | 15 (3) | 16 (3) | 15 (3) | 0.076 |
| Current occupation | |||||
| Employed | 61 (41%) | 22 (34%) | 26 (53%) | 13 (36%) | 0.096 |
| Retired | 22 (15%) | 10 (15%) | 7 (14%) | 5 (14%) | 0.975 |
| Long-term sick leave | 35 (23%) | 17 (26%) | 5 (10%) | 13 (36%) | 0.016 |
| Unemployed/other | 32 (21%) | 16 (25%) | 11 (22%) | 5 (14%) | 0.440 |
| Follow-up, mean (SD) days | 383 (47) | 382 (40) | 393 (50) | 373 (54) | 0.202 |
Data presented as n (%), if not specified otherwise. Total sample size: an = 144; bn = 143; cn = 145; dn = 140; and en = 136. Because of rounding, percentages might not add up to 100% exactly
DM1 myotonic dystrophy type 1
†Comparing patients with a higher DM1-ActivC total score, same score, and lower score at follow-up