Table 2. Proportion of patients with and without cognitive impairmenta at baseline and years 1, 3 (end of core study), and 5 (end of extension study).
| Baseline | Year 1 | Year 3 | Year 5 | |||||
| IFN β-1a sc tiw group | With impairment, n (%) | Without impairment, n (%) | With impairment, n (%) | Without impairment, n (%) | With impairment, n (%) | Without impairment, n (%) | With impairment, n (%) | Without impairment, n (%) |
| 44 µg (n = 69) | 10 (14.5) | 59 (85.5) | 14 (20.3) | 55 (79.7) | 12 (17.4) | 57 (82.6) | 14 (20.3) | 55 (79.7) |
| 22 µg (n = 64) | 14 (21.9) | 50 (78.1) | 16 (25.0) | 48 (75.0) | 13 (20.3) | 51 (79.7) | 16 (25.0) | 48 (75.0) |
| All patients (n = 133) | 24 (18.0) | 109 (82.0) | 30 (22.6) | 103 (77.4) | 25 (18.8) | 108 (81.2) | 30 (22.6) | 103 (77.4) |
a
Defined as impaired performance on ≥3 tests of the Rao's Brief Repeatable Battery and Stroop Color–Word Task.
Cochran test = 0.392.
IFN = interferon; sc = subcutaneously; tiw = three times weekly.