Table 2.
Characteristics of patients according to phenotypes.
| Phenotype | Bulbar, N (%), Mean [SD] | Classic, N (%), Mean [SD] | Flail Arm, N (%), Mean [SD] | Flail Leg, N (%), Mean [SD] | UMNp, N (%), Mean [SD] | Respiratory, N (%), Mean [SD] | Unknown, N (%), Mean [SD] |
p-Value |
|---|---|---|---|---|---|---|---|---|
| Mean age at onset, years | 69.84 [10.69] | 64.84 [11.38] | 65.01 [10.53] | 65.67 [11.47] | 61.57 [12.68] | 70.35 [6.08] | 67.50 [10.97] | <0.001 |
| Mean age at diagnosis, years | 70.74 [10.70] | 66.05 [11.44] | 66.38 [10.40] | 67.11 [11.16] | 63.41 [12.75] | 71.30 [6.24] | 68.52 [10.87] | <0.001 |
| ALSFRS-R score at diagnosis | 38.31 [7.71] | 38.58 [7.52] | 38.69 [8.57] | 38.94 [6.72] | 39.06 [6.99] | 34.07 [9.30] | 36.00 [18.07] | 0.095 |
| Progression rate at diagnosis * | 1.27 [1.57] | 0.92 [0.98] | 0.67 [0.72] | 0.68 [0.65] | 0.75 [0.78] | 1.67 [1.65] | 0.61 [0.45] | <0.001 |
| Progression rate, first to last visit # | 1.55 [2.08] | 1.36 [1.67] | 1.33 [1.51] | 1.25 [1.71] | 0.87 [1.08] | 1.74 [2.60] | 1.58 [2.64] | 0.151 |
| FVC at diagnosis | 77.15 [25.83] | 88.78 [25.59] | 92.04 [23.84] | 88.03 [23.23] | 95.11 [21.48] | 62.05 [17.29] | 83.00 [14.14] | <0.001 |
| Monthly FVC decline § | 2.89 [4.53] | 2.82 [3.69] | 2.25 [3.96] | 2.17 [3.54] | 2.14 [3.34] | 0.46 [3.11] | 3.36 [3.44] | 0.323 |
| FTD | 50 (10.99) | 47 (8.29) | 5 (7.94) | 2 (1.67) | 6 (7.59) | 1 (3.33) | 2 (0.74) | 0.032 ** |
| Family history of ALS/FTD | 61 (13.41) | 99 (17.46) | 12 (19.05) | 13 (10.83) | 5 (6.33) | 4 (13.33) | 7 (2.58) | 0.089 *** |
| Total | 455 (28.20) | 567 (35.15) | 63 (3.91) | 120 (7.44) | 79 (4.90) | 30 (1.86) | 271 (16.80) |
Table 2 shows differential distribution of main clinical features among phenotypes, tested with chi-square test or ANOVA as appropriate. FVC: forced vital capacity; FTD: frontotemporal dementia; UMN-p: Upper Motor Neuron predominant. * Progression rate at diagnosis was calculated as monthly decline in ALSFRS-R score assuming a total score of 48 at onset; it was calculated for 1159 patients in total. # Progression rate from first to last visit was calculated as monthly decline in ALSFRS-R score from the first to the last available visit or from the first visit to the first time when a total score of 0 was recorded (whichever came first). It was calculated for 1049 patients in total. § Monthly decline in FVC was calculated for 600 patients in total, considering first FVC% value, the last available FVC% value and time between the first and last FVC. ** single comparisons showed a different frequency of FTD between classic and flail leg (p = 0.010), flail arm and flail leg (p = 0.032), flail leg and UMNp (p = 0.037) phenotypes; *** single comparisons among phenotypes showed a different frequency of family history between classic and UMNp (p = 0.012), flail arm and UMNp (p = 0.020) phenotypes.