To compare the time from first joint swelling to fulfillment of the American College of Rheumatology/European League Against Rheumatism classification criteria between patients with seropositive and seronegative rheumatoid arthritis (RA) and to assess the impact of seronegative status on the time from first joint swelling to initiation of disease-modifying antirheumatic drug (DMARD) therapy and achievement of remission.
Times from first provider-documented joint swelling to fulfillment of the 1987 and 2010 American College of Rheumatology/European League Against Rheumatism criteria and to the clinical diagnosis of RA were measured in a population-based cohort of adults with incident RA between January 1, 2009, and December 31, 2014. Disease characteristics and achievement of remission were compared between seropositive (rheumatoid factor positive and/or anti-citrullinated peptide antibody positive) and seronegative (rheumatoid factor negative/anti-citrullinated peptide antibody negative) patients.
The median time from first joint swelling to fulfillment of the 1987 (48 [interquartile range (IQR), 0-300] days vs 2 [IQR, 0-45] days; P=.001) and 2010 (14 [IQR, 0-196] days vs 0 [IQR, 0-29] days; P=.004) classification criteria and the median time from first joint swelling to the clinical diagnosis of RA (187 [IQR, 13-503] days vs 11 [IQR, 0-76] days; P<.001) were significantly longer in seronegative patients than in seropositive patients. The median time from first joint swelling to first prescribed DMARD therapy was significantly longer in seronegative patients (40 [IQR, 5-199] days vs 14 [IQR, 0-73] days; P=.01). Patients with seronegative RA were less likely to achieve remission (28% vs 50% at 5 years after fulfillment of the 2010 criteria; P=.007), but there was no difference when the patient global score was removed from the remission definition.
Patients with seronegative RA experienced a delay in diagnosis, according to both the 1987 and 2010 classification criteria, as well as a delay in the initiation of DMARD therapy. Patients with seronegative RA were also less likely to attain remission, suggesting that the window of opportunity for intervention may be more frequently missed in this group.