Background/Purpose: The rheumatoid factors (RF) have established roles in rheumatoid arthritis (RA) diagnosis, prediction of disease onset and drug response, and in classifying patients as to prognosis. We assessed the influences of RF presence and titration on real-life management outcomes in a large multicenter RA cohort. 

Methods: From August, 2015 to April, 2016, the REAL Study enrolled adult patients diagnosed with RA, according to ARA (1987) or ACR/EULAR (2010) criteria, from eleven Brazilian tertiary healthcare centers. Structured clinical interview and assessment of medical records were performed. DAS28-ESR score, treat to target (T2T) goal attainment (DAS28-ESR < 3.2), disability (HAQ), RF titers, and the presence of erosive disease (EULAR definition) were assessed, as well as several other clinical and demographic variables. A high-titer RF was defined as ≥ 3x the upper limit of normality. Student’s t test, Mann-Whitney U, Kruskal-Wallis test, chi-square, and Fisher’s exact test were used as appropriate.

Results: 1116 patients were included; 89.4% female and 56.8% white. The mean (SD) age was 57.1 (11.5) years; disease duration: 174.7 (115.1) months; schooling years: 8.3 (4.7). Mean DAS28-ESR was 3.6 (1.5); HAQ score 0.943 (0.769). Only 41.3% of patients were within the T2T goal for DAS28. RF was positive in 78.6% of all patients, and in high titers in 56.1%. Erosive disease was found in 54.9%. The median delay from first symptoms to first DMARD was 12 months (IQR=36). RF titers categories (negative, low and high positive) were comparable as to background characteristics: gender, race, age, disease duration, schooling years, and delay from first symptoms to first DMARD (p >0.05 for all comparisons).  The high-titer RF category as compared to the non-high (combined negative or low-titer) RF category showed higher DAS28-ESR scores [3.8(1.5) vs. 3.4(1.5); p< 0.001]; higher HAQ scores [0.999(0.796) vs. 0.870(0.728); p=0.012]; lower attainment of T2T goals [37.2% vs. 46.9%; OR 0.67 (95%CI: 0.51—0.87)]; higher usage of corticosteroids [52.4% vs. 40.2%; OR 1.64 (95%CI: 1.29—2.08)]; higher biological DMARD usage [39.3% vs. 30.9%; OR 1.45 (95%CI: 1.12—1.86)], and higher frequency of extra-articular manifestations [26% vs. 19.6%; OR 1.45 (95%CI: 1.08—1.92)]. Negative and positive low-titer RF categories showed no significant differences between themselves, as to any of the aforementioned outcome variables. Erosive disease was not associated with the RF titer categories (p=0.097).

Conclusion: High-titer RF was associated with worse outcomes in real-life management of RA, with higher disease activity and disability, lower attainment of T2T goals, higher usage of both corticosteroids and biological DMARDs, and higher frequency of extra-articular manifestations. Erosive disease was not associated with RF titer categories in this study, possibly because of the long delay in initiating DMARDs in all RF titer categories, and the overall high frequency of erosions in this population.  Negative and low-titer RF categories seemed to perform similarly, regarding clinical outcomes in real-life management of rheumatoid arthritis. 

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/high-titer-rheumatoid-factor-impacts-real-life-management-outcomes-of-rheumatoid-arthtitis/