Burgers LE, et al. - The purpose of this study is to assess whether there are phenotypic differences in the symptomatic pre-RA phase. This is the first study exhibiting that anticitrullinated protein antibody (ACPA)-positive and ACPA-negative patients have clinical differences in the symptomatic phase preceding clinical arthritis. This contributes to the notion that ACPA-positive and ACPA-negative RA develop differently.

Methods

• For this research, they designed a longitudinal study.
• Patients with arthralgia incorporated into the Leiden clinically suspect arthralgia cohort who developed arthritis amid follow-up were studied (n=67).
• Symptoms at symptom onset, symptoms and signs at presentation with arthralgia and time to arthritis development were compared between ACPA-positive and ACPA-negative patients.

Results

• The outcome showed that the location of initial symptoms less often included the lower extremities (22% vs 50%, p=0.014) in ACPA-negative patients (n=37).
• At presentation with arthralgia, ACPA-positive patients had a longer symptom duration (median 22 vs 14 weeks, p=0.005), less tender joints (mean 5 vs 9, p=0.007) and less difficulty making a fist (11% vs 43%, p=0.004).
• However, after presentation with arthralgia, ACPA-positive patients developed arthritis more quickly (median 6 vs 18 weeks, p=0.015).
• A partial least squares regression examination demonstrated clustering of ACPA-positive and ACPA-negative patients based on the above-mentioned clinical variables.