COVID-19 severity among patients with multiple sclerosis treated with cladribine: A systematic review and meta-analysis

BACKGROUND: The Coronavirus 19 pandemic has raised new relevant questions regarding the management of patients with multiple sclerosis (pwMS) treated with different immunosuppressive and immunomodulant drugs. In most COVID-19 outcomes analyses, due to the small available sample size, patients treated with cladribine were grouped with patients treated with other treatments. METHODS: Three major databases (PubMed, Scopus and Web of Science) and the most recent MS congress libraries were searched for extracting original articles on COVID-19 and multiple sclerosis. The key inclusion criteria were the presence of data on pwMS treated with cladribine and with documented positivity for COVID-19. The quality of the included studies was evaluated using a modified version of the Dutch Cochrane center critical review checklist proposed by MOOSE. A common-effect meta-analysis was used for estimating the pooled proportion of patients with severe events (hospitalizations, pneumonia, ICU admissions and deaths) and heterogeneity was assessed by the I(2) statistic. RESULTS: 13 articles were included in the analysis and the median quality of the articles reached a level of 4. The selected studies included 5138 patients with COVID-19, of whom 107 (2.1%) were treated with cladribine. Pooled estimates of hospitalization and death were 9.36% and 0% for patients treated with cladribine, 14.98% and 2.66% for pwMS under other treatments. CONCLUSION: These results indicate that pwMS treated with cladribine are not at a greater risk of developing a severe form of COVID-19. REGISTRATION: The protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO: CRD42022329464),