Prevalence and Risk of Anemia in People With Multiple Sclerosis (MS): A Systematic Review and Meta-Analysis

Anemia appears as a common comorbidity in a different timing and underlying pathophysiology in people with MS (PwMS) and has been proposed as a prodrome finding in MS. This systematic review and meta-analysis aims to fulfill the need to clarify some characteristics of anemia in PwMS.

A systematic literature search was performed using the MEDLINE PubMed, Scopus, and Google Scholar databases. Eligible studies underwent quality assessment using the Robins-E, and a meta-analysis of proportion was performed. The risk of anemia in PwMS versus healthy controls was calculated based on a subset of case-control studies. Reliability and robustness were assessed using leave-one-out analysis.

In a pool of 143,879 PwMS across 21 studies, anemia had a pooled prevalence of 12.5% (95% CI [8.1%, 17.7%], I ²  = 99.0%, p _Q  = 0). In a subset of five studies, the relative risk of anemia between PwMS and healthy controls was 2.9 (95% CI [1.45, 5.79], I ² = 97.6%, p _z  = 0.002, p _Q  < 0.001) in favor of PwMS.

The intersection between anemia and MS presents a complex, multifaceted clinical challenge due to several pathophysiological mechanisms and DMT-related interactions. Further structured studies are needed to evaluate the exact underlying mechanisms and the directionality of this relationship.