Table 1.
Baseline characteristics of the matched study population by COVID cases versus controls.
| Baseline factor | Category/metric | Cases (n = 2161) | Controls (n = 2161) | Standardised difference |
|---|---|---|---|---|
| Age | Mean (SD) | 40.63 (11.41) | 40.45 (11.68) | 0.02 |
| Sex | Female | 1506 (69.7) | 1515 (70.1) | −0.01 |
| Male | 655 (30.3) | 646 (29.9) | ||
| Disease duration (years) | Mean (SD) | 9.71 (8.18) | 9.94 (7.23) | −0.03 |
| Baseline EDSS | Median (IQR) | 1.5 (1–3) | 1.5 (1–3) | 0.02 |
| MS course | CIS | 177 (8.2) | 154 (7.1) | 0.03 |
| PP | 76 (3.5) | 139 (6.4) | ||
| PR | 24 (1.1) | 21 (1.0) | ||
| RR | 1751 (81.0) | 1733 (80.2) | ||
| SP | 133 (6.2) | 96 (4.4) | ||
| Not reported | 0 (0.0) | 18 (0.8) | ||
| Relapses 1-year pre-baseline | Mean (SD) | 0.07 (0.30) | 0.07 (0.29) | −0.02 |
| Relapses 2-year pre-baseline | Mean (SD) | 0.10 (0.43) | 0.11 (0.39) | −0.03 |
| DMT class | High efficacy | 1058 (49.0) | 1109 (51.3) | 0.03 |
| Low-moderate efficacy | 746 (34.5) | 686 (31.7) | ||
| No baseline DMT | 357 (16.5) | 366 (16.9) | ||
| Country | Argentina | 20 (0.9) | 67 (3.1) | −0.03 |
| Australia | 254 (11.8) | 271 (12.5) | ||
| Belgium | 52 (2.4) | 109 (5.0) | ||
| Brazil | 21 (1.0) | 19 (0.9) | ||
| Spain | 231 (10.7) | 177 (8.2) | ||
| Croatia | 179 (8.3) | 7 (0.3) | ||
| Italy | 285 (13.2) | 93 (4.3) | ||
| Kuwait | 137 (6.3) | 363 (16.8) | ||
| Mexico | 3 (0.1) | 2 (0.1) | ||
| Romania | 3 (0.1) | 2 (0.1) | ||
| Saudi Arabia | 9 (0.4) | 27 (1.3) | ||
| Turkey | 967 (44.8) | 1024 (47.4) |
Values are expressed as n (%), median (IQR) or mean (SD). Standardised difference is the difference in means or proportions divided by the standard error. An imbalance was defined as an ASD > 0.10.
CIS, clinically isolated syndrome; DMT, disease-modifying therapy; EDSS, Expanded Disability Status Scale; IQR, interquartile range; MS, multiple sclerosis; PP, primary progressive; PR, progressive relapsing; RR, relapsing remitting; SD, standard deviation; SP, secondary progressive.