Objective This study was undertaken to assess the impact of immunosuppressive and immunomodulatory therapies on the severity of coronavirus disease 2019 (COVID‐19) in people with multiple sclerosis (PwMS). Methods We retrospectively collected data of PwMS with suspected or confirmed COVID‐19. All the patients had complete follow‐up to death or recovery. Severe COVID‐19 was defined by a 3‐level variable: mild disease not requiring hospitalization versus pneumonia or hospitalization versus intensive care unit (ICU) admission or death. We evaluated baseline characteristics and MS therapies associated with severe COVID‐19 by multivariate and propensity score (PS)‐weighted ordinal logistic models. Sensitivity analyses were run to confirm the results. Results Of 844 PwMS with suspected (n = 565) or confirmed (n = 279) COVID‐19, 13 (1.54%) died; 11 of them were in a progressive MS phase, and 8 were without any therapy. Thirty‐eight (4.5%) were admitted to an ICU; 99 (11.7%) had radiologically documented pneumonia; 96 (11.4%) were hospitalized. After adjusting for region, age, sex, progressive MS course, Expanded Disability Status Scale, disease duration, body mass index, comorbidities, and recent methylprednisolone use, therapy with an anti‐CD20 agent (ocrelizumab or rituximab) was significantly associated (odds ratio [OR] = 2.37, 95% confidence interval [CI] = 1.18–4.74, p = 0.015) with increased risk of severe COVID‐19. Recent use (<1 month) of methylprednisolone was also associated with a worse outcome (OR = 5.24, 95% CI = 2.20–12.53, p = 0.001). Results were confirmed by the PS‐weighted analysis and by all the sensitivity analyses. Interpretation This study showed an acceptable level of safety of therapies with a broad array of mechanisms of action. However, some specific elements of risk emerged. These will need to be considered while the COVID‐19 pandemic persists. ANN NEUROL 2021;89:780–789

Background: Neuropsychological deficits in patients with multiple sclerosis (MS) have been shown to be associated with the major pathological substrates of the disease, ie, inflammatory demyelination and neurodegeneration. Double inversion recovery sequences allow cortical lesions (CLs) to be detected in the brain of patients with MS. Modern postprocessing techniques allow cortical atrophy to be assessed reliably.Objective: To investigate the contribution of cortical gray matter lesions and tissue loss to cognitive impairment in patients with relapsing-remitting MS.

Cortical inflammatory lesions have been correlated with disability and cortical atrophy in multiple sclerosis. The extent to which cortical lesion load is associated with longer-term physical and cognitive disability in different multiple sclerosis phenotypes has not yet been investigated. Thus, a 5-year prospective longitudinal study was carried on in a large group of patients with multiple sclerosis. Three hundred and twelve consecutive patients suffering from multiple sclerosis (157 relapsing remitting, 35 paediatric, 45 benign, 44 primary progressive and 31 secondary progressive) were enrolled in a 5-year prospective clinical and neuroimaging study. Several magnetic resonance parameters (including cortical lesion number and volume, contrast-enhancing cortical lesions and grey matter atrophy) were analysed to find associations with clinical and cognitive outcomes. Patients with high cortical lesion load had higher Expanded Disability Status Scale increase (median = 1.5; range = 0-3) during the study than both patients with low cortical lesion load (median = 1.0; range = 1-3, P < 0.001) and without cortical lesions (median = 0.5; range = -1 to 2, P < 0.001). Compared with clinically stable patients, 101 (32.4%) patients showing clinical progression at 5 years had the highest rate of cortical lesion accumulation (P < 0.001). Stepwise regression analysis revealed significant and independent contributions from age (β = 0.55), cortical lesion volume (β = 0.58), T(2) white matter lesion volume (β = 0.34) and grey matter fraction (β = 0.42) as predictors (final model with r(2 )= 0.657, P < 0.001) of Expanded Disability Status Scale change. Disease duration (β = 0.52, P < 0.001), cortical lesion volume (β = 0.67, P < 0.001), grey matter fraction (β = 0.56, P < 0.001) and T(2) white matter lesion volume (β = 0.31, P = 0.040) at baseline were found to be independent predictors of cognitive status at the end of the study. While confirming the relevance of cortical pathology in all multiple sclerosis phenotypes, but benign, our study suggests that grey matter and white matter changes in multiple sclerosis occur, at least, partly independently, and that grey matter, more than white matter, damage is associated with physical and cognitive disability progression. Thus, the combination of grey and white matter parameters gives a more comprehensive view of multiple sclerosis pathology and allows a better understanding of the progressive phase of the disease, which, however, seems more related to cortical damage than to subcortical white matter changes.

The regional analysis of deep and cortical grey matter atrophy suggests an association between the neurodegenerative process taking place in the striatum-thalamus-frontal cortex pathway and the development of fatigue in relapsing-remitting multiple sclerosis. The inclusion of the posterior parietal cortex as one of the best predictors of the Modified Fatigue Impact Scale cognitive domain suggests the major role of the posterior attentional system in determining cognitive fatigue in relapsing-remitting multiple sclerosis.

Selective GM atrophy is relevant in patients with CIS who convert early to MS. The inclusion of GM analysis in the MS diagnostic workup is worthy of further investigation.