Table 1.
Baseline characteristics
| All patients (n = 126) | Treatment-refractory (n = 14) | Treatment-responsive (n = 112) | p value* | |
|---|---|---|---|---|
| Sex | 0.25 | |||
| Male | 54 (42.9%) | 8 (57.1) | 46 (41.1%) | |
| Female | 72 (57.1%) | 6 (42.9%) | 66 (58.9%) | |
| Median age | 49.5 years (IQR 37) | 33 years (IQR 25) | 50.5 (IQR 38) | 0.035‡ |
| EOMG (< 50 years) | 63 (50%) | 11 (78.6%) | 52 (46.4%) | 0.023‡ |
| Antibodies | 0.085 | |||
| AChR | 109 (86.5%) | 10 (71.4%) | 99 (88.4%) | |
| MuSK | 8 (6.3%) | 1 (7.1%) | 7 (6.3%) | |
| Seronegative** | 9 (7.1%) | 3 (21.4%) | 6 (5.4%) | |
| Median AChR-Ab titer at onset |
17.2 (IQR 27.85) |
9.9 (IQR 16.6) | 17.5 (IQR 29.2) | 0.42 |
| MGFA class at onset | 0.96 | |||
| 1 | 31 (24.6%) | 4 (28.6%) | 27 (24.1%) | |
| 2 | 77 (61.1%) | 9 (64.3%) | 68 (60.7%) | |
| 3 | 13 (10.3%) | 1 (7.1%) | 12 (10.7%) | |
| 4 | 3 (2.4%) | 0 | 3 (2.7%) | |
| 5 | 2 (1.6%) | 0 | 2 (1.8%) | |
| Max. MGFA class | < 0.000‡ | |||
| 2 | 68 (54%) | 0 | 68 (60.7%) | |
| 3 | 31 (24,6%) | 9 (64.3%) | 22 (19.6%) | |
| 4 | 18 (14.3%) | 4 (28.6%) | 14 (12.5.%) | |
| 5 | 9 (7.1%) | 1 (7.1%) | 8 (7.1%) | |
| Thymectomy | 68 (54%) | 10 (71.4%) | 58 (51.8%) | 0.16 |
| Thymus histology | 0.62 | |||
| Normal | 29 (42.7%) | 3 (30%) | 26 (44.8%) | |
| Hyperplasia | 20 (29.4%) | 4 (40%) | 16 (27.6%) | |
| Thymoma | 17 (25%) | 3 (30%) | 14 (24.1%) | |
| No data | 2 (2.9%) | 0 | 2 (3.5%) | |
| Severe comorbidity | 23 (18.3%) | 3 (21.4%) | 20 (17.9%) | 0.74 |
| Median time onset to IST (months) | 3 (IQR 9) | 2.5 (IQR 9) | 3 (IQR 9) | 0.61 |
Baseline characteristics of all patients and comparison of treatment-refractory and treatment-responsive patients
AChR denotes acetylcholine receptor, MG myasthenia gravis, MGFA Myasthenia Gravis Foundation of America, MuSK muscle-specific tyrosine kinase, EOMG early-onset myasthenia gravis, IS immunosuppressive, IQR interquartile range, NA not applicable
*p values were obtained with the Mann–Whitney U or Student’s t test (for continuous variables) and the Chi-square test (for categorical variables) as appropriate
**Of the 10 seronegative patients 4 [2 of whom were treatment-refractory) were tested negative for antibodies against AChR by radioimmunoassay (RIA)], MuSK, LRP4 and AChR by cell binding assay, 5 (one of whom were treatment-refractory) against AChR (RIA) and MuSK and 1 against AChR (RIA) only
‡Statistically significant