Does early seronegative arthritis develop into rheumatoid arthritis? A 10-year observational study

Area of Science:

• Rheumatology
• Clinical Immunology
• Epidemiology

Background:

• Seronegative arthritis, defined by the absence of rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA), presents a diagnostic challenge.
• Understanding the long-term clinical course and diagnostic evolution of seronegative arthritis is crucial for effective patient management.

Purpose of the Study:

• To investigate the 10-year clinical course of patients initially diagnosed with seronegative arthritis.
• To reclassify diagnoses based on updated clinical information and evolving diagnostic criteria over the follow-up period.

Main Methods:

• A cohort of 435 patients with early seronegative arthritis was prospectively followed for 10 years.
• Retrospective review of clinical data and reclassification of diagnoses were performed using descriptive statistics.

Main Results:

• Only 3% of seronegative cases were reclassified as seropositive or erosive rheumatoid arthritis (RA).
• Significant heterogeneity was observed, with reclassifications including polymyalgia rheumatica (16%), psoriatic arthritis (11%), osteoarthritis (10%), and spondyloarthritis (8.7%).
• A substantial proportion (32%) remained unclassifiable into a clear-cut diagnosis, with features of transient arthritis or unspecified conditions.

Conclusions:

• The 10-year follow-up demonstrates considerable heterogeneity within the initial diagnosis of seronegative arthritis.
• Seronegative arthritis should not be considered a homogenous entity in research or clinical practice.
• Individualized diagnostic approaches are essential for patients presenting with seronegative arthritis.