Progression from seropositive arthralgia to rheumatoid arthritis: One-year predictors from a large cohort in the Reuma-Check program.

BACKGROUND

Seropositive arthralgia (SA), defined as joint pain without clinical synovitis in individuals positive for rheumatoid factor (RF) and/or anti-citrullinated protein antibodies (ACPA), is considered a preclinical stage of rheumatoid arthritis (RA). Early identification of individuals at risk is key for timely intervention.

OBJECTIVES

To estimate the prevalence of SA in a large early arthritis cohort, compare its baseline features with RA, and identify predictors of progression to RA at one year.

METHODS

This prospective study was conducted within Reuma-Check, a structured diagnostic program for early rheumatologic assessment in Argentina. Patients with SA and RA were identified based on standardized clinical, serological, and imaging assessments. SA patients were followed for 12 months. Logistic regression was used to identify independent predictors of RA development.

RESULTS

Among 1730 patients, 208 (12%) were classified as SA and 225 (13%) as RA. Compared to RA, SA patients had fewer tender and swollen joints, lower inflammatory markers, and less Power Doppler positivity on ultrasound. At one year, 21% of SA patients progressed to RA, 14% developed other immune-mediated conditions, and 65% remained stable. In multivariate analysis, ACPA positivity was the only independent predictor of RA progression (OR: 7.7, 95% CI: 1.2-60).

CONCLUSIONS

In the Reuma-Check cohort, among individuals with seropositive arthralgia, ACPA positivity is the most robust predictor of progression to rheumatoid arthritis at 1 year.