Research Article

Bimonthly Evolution of Cortical Atrophy in Early Relapsing-Remitting Multiple Sclerosis over 2 Years: A Longitudinal Study

Table 1

Descriptive statistics of demographic, clinical, and MRI variables at baseline.

Total ( )Early group ( )Late group ( ) value*

Sex, females (%)108 (79.4%)32 (86.5)76 (76.8)0.243
Age in years, mean (SD) min–max30.9 (7.9) 19–5627.3 (6.7) 19–5032.2 (7.9) 19.6–560.001
Age at onset in years, mean (SD) min–max23.9 (7.1) 12–5124.8 (6.5) 18–4823.5 (7.3) 12–510.345
Annual relapse rate, mean (SD) min–max1.8 (0.8) 0–42 (0.83) 0–41.8 (0.7) 0–30.064
Disease duration in years, mean (SD) median (min–max)5.5 (5.2) 3.9 ( 0.6–32.5)1.24 (0.37) 1.2 (0.6–2)7.1 (5.3) 5.4 (2.1–32.5)<0.0001
EDSS, mean (SD) median (min–max)1.9 (0.9) 2.0 (0–4.0)1.5 (0.9) 1.5 (0–3.5)2.1 (0.9) 2.0 (0–4.0)0.002
Normalized WBV, mean (SD) min–max1494 (76.7) 1303.1–1667.11524.3 (64.8) 1393.3–1649.81482.6 (77.9) 1303.1–1667.10.014
Normalized CV, mean (SD) min–max587.5 (44.2) 478.9–685.9608 (34.7) 537.8–685.9579.8 (45.1) 478.8–670.30.002
T2-LV, mean (SD) min–max10 (11.1) 0.1–58.35.9 (6.4) 0.1–24.211.5 (12.1) 0.2–58.30.01

EDSS: expanded disability status scale, WBV: whole brain volume, CV: cortical volume, and LV: lesion volume.
Annual relapse rate refers to the mean number of relapses in the year before baseline.
The statistical differences between early and late disease duration groups ( value*) were calculated using the chi-square test, Student’s -test, and Mann-Whitney rank-sum test, as appropriate.
The volumes are reported in milliliters.