Repurposing the Fibrosis-4 Score in Rheumatoid Arthritis: Data from the ESPOIR Cohort.

Background: We aimed to evaluate the value of the Fibrosis-4 (FIB-4) score as a prognostic factor in RA in the prospective ESPOIR cohort. Methods: We included patients from the ESPOIR cohort with a diagnosis of RA according to ACR/EULAR criteria. The formula for the FIB-4 score is as follows: [age (years) × aspartate transaminase level (U/L)]/[platelet count (10 ⁹ /L) × alanine aminotransferase level (U/L) ^1/2 ]. We used a linear mixed-effects model with a random effect of patient to account for repeated measures over time. Results: Overall, 647 of the 813 patients included met the ACR/EULAR criteria for RA, with no differential diagnosis during the first 10 years of follow-up. Of these patients, at baseline, 633 had a calculable FIB-4 score. Median FIB-4 score was 0.75 (interquartile range 0.53-0.99). On multivariate analysis, FIB-4 score was not independently associated with progression of Disease Activity Score in 28 joints over 10 years of follow-up, unlike baseline C-reactive protein level and SJC. Baseline FIB-4 score was not associated with the modified Sharp score at 5-year follow-up, unlike age and ACPAs. FIB-4 score was not associated with mortality (hazard ratio 1.1 [95% CI 0.46; 2.8], p = 0.77) or major adverse cardiovascular events (0.46 [0.13; 1.6], p = 0.22) over the 10-year follow-up. No significant change in FIB-4 score over time was related to treatments. Conclusions: The present prospective cohort study did not find a prognostic role of FIB-4 score in RA. Reassuringly, FIB-4 score was not increased with DMARD treatment after 10 years of follow-up.