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TOPLINE:

Patients who test positive for anti-citrullinated protein antibodies (ACPAs) had a longer gap from symptom onset to specialist presentation but experienced faster progression to rheumatoid arthritis (RA) after presentation and had a faster rise in C-reactive protein (CRP) levels, whereas those negative for ACPA had more persistent morning stiffness and tender hand joints before the onset of RA.

METHODOLOGY:

• Researchers in Netherlands analyzed data from an observational cohort and the placebo group of a previous trial to assess whether the trajectory from symptom onset to RA differed by ACPA status.
• They included 173 patients (72% women) with clinically suspect arthralgia who later developed inflammatory arthritis between 2012 and 2024.
• Patients were categorized into the ACPA-negative group (n = 87; mean age, 46 years) and the ACPA-positive group (n = 86; mean age, 49 years).
• Assessments included morning stiffness, a tender joint count based on 68 joints, blood CRP levels, and contrast MRI of the hands and feet. Inflammatory arthritis was defined as development of at least one swollen joint based on a 66-joint examination.
• Researchers compared the time from symptom onset to presentation with clinically suspect arthralgia and from that presentation to the development of the first swollen joint, with visits at 4, 12, and 24 months and up to 5 years of follow-up for some patients.

TAKEAWAY:

• The ACPA-positive group had a longer time between symptom onset and presentation with clinically suspect arthralgia than the ACPA-negative group (median, 24 weeks vs 16 weeks; P = .006) but a shorter time from presentation to development of inflammatory arthritis (median, 12 weeks vs 21 weeks; P = .014).
• The ACPA-negative group more often reported morning stiffness at symptom onset (70% vs 54%; P = .024), had higher stiffness scores at presentation (P < .050), and continued to experience greater stiffness over time than the ACPA-positive group.
• Patients in the ACPA-negative group had more tender joint counts (median, 5 vs 3; P < .001), especially more tender hand joints. The difference persisted over time.
• In the months before diagnosis of clinical arthritis, the increase in CRP levels was faster in the ACPA-positive group (P = .006), with greater subclinical foot inflammation on MRI (P < .050). 

IN PRACTICE:

“These differences may reflect differences in underlying inflammatory mechanisms and suggest that different preventive strategies are needed to intervene in the development of ACPA-positive and ACPA-negative RA,” the authors wrote.

SOURCE:

This study was led by Mitra Hosseini Malekroudi, Leiden University Medical Center in Leiden, Netherlands. It was published online on May 27 in Annals of the Rheumatic Diseases.

LIMITATIONS:

The number of MRI scans differed between the two datasets. Symptom duration was self-reported and may have been affected by recall bias. Only CRP was measured as a marker for inflammation.

DISCLOSURES:

This study received support from the Dutch Arthritis Society. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.