In statistical models, neurofilament light chain (Nlf) levels exhibited weaker connections with progression independent of relapse activity (PIRA)—”silent progression”—risk, while glial fibrillary acidic protein (GFAP) levels indicated very significant associations. Further models revealed that, whereas high NfL levels were linked to an approximately doubled risk of disability worsening, high levels of GFAP were associated with a nearly threefold higher risk of disability worsening. In contrast to low levels of both proteins, high levels of GFAP and NfL were linked to a more than fourfold probability of disease deterioration. Overall, the data, according to the researchers, support NfL as a biomarker of relapse activity and GFAP as a useful biomarker for predicting the likelihood of PIRA. The analysis of both markers provides “complete coverage of biological mechanisms contributing to disability worsening” as a result.