Fibromyalgia with elevated rheumatoid factor is associated with poor therapeutic response but not with progression to rheumatoid arthritis. Prospective cohort study

Liñán Ponce F.; Leiva Goicochea J.; Sevilla Rodríguez D.; Hidalgo Bravo E.; Obregón Atanacio G.; Loyola Macalapú I.; Jáuregui Rojas P.; Yampufe Canani J. · Reumatologia Clinica (2024) · DOI: 10.1016/j.reuma.2024.06.005

Resumen

Objective: Evaluate response to treatment and progression to rheumatoid arthritis (RA) in patients with fibromyalgia (FM) associated with elevated rheumatoid factor (RF). Material and methods: Prospective cohort study. The sample consisted of 124 patients with FM: 62 with high RF (> 20 U/ml) and 62 with negative RF (0-20 U/ml). All patients were evaluated using FM treatment improvement score (FIQR) and progression to RA according to EULAR/ACR 2010 criteria at 6 and 12 months. Pearson's χ2 test for homogeneity was used to relate variables of improvement to FM treatment and progression to RA. Results: The response to treatment was lower in the high RF group (24 and 20 patients improved at 6 and 12 months, respectively, compared to 45 and 38 patients in the negative RF group), with a significant difference. Progression to rheumatoid arthritis was similar in both groups (5 in the high RF group and 4 in the negative RF group), with a non-significant relationship. Conclusions: FM with elevated RF is associated with a poor therapeutic response but not with progression to RA.