About 70% of patients with rheumatoid arthritis (RA) in any clinical cohort are seropositive.1 In early RA cohorts, barely 50% are seropositive indicating that a diagnosis of RA can be established without serological markers. However, there is evidence that seropositive and seronegative RA behave differently in short term studies: van Dongen et al2 showed that in anti citrulline peptide (CCP) positive patients, early MTX therapy postponed diagnosis of RA and prevented erosions statistically significantly better compared to placebo, which difference could not be seen in CCP negative patients. Few long-term studies have re-evaluated patients who have received a diagnosis of seronegative RA. In a 23-year follow-up study, Jäntti et al3;4 showed that psoriatic arthritis and mild spondylarthropaties are common in these patients.
Early RA is an emergency case; patients have to be treated without delay to prevent damage, functional deterioration, work disability, and other consequences of inflammatory joint diseases. As diagnosis of RA is based on consensus criteria, patients with inflammatory joint diseases that mimic early RA can be included in early RA cohorts. Only careful follow-up of patients over many years and re-evaluation of diagnosis in all patients will reveal diagnoses behind symptoms that were classified as seronegative RA.
We present seronegative cases who were classified and treated as early rheumatoid arthritis and were later revealed various diagnoses. The objective of this session is to remind of the necessity to re-evaluate diagnosis of patients with persistent seronegative “RA”. Sometimes wrong diagnosis may be a reason for poor response to anti rheumatic medications.
Sokka T, Kautiainen H, Pincus T, Toloza S, da Rocha Castelar PG, Lazovskis J et al. Disparities in rheumatoid arthritis disease activity according to gross domestic product in 25 countries in the QUEST-RA database. Ann Rheum Dis 2009; 68(11):1666-1672.
van Dongen H, van Aken J, Lard LR, Ronday H.K, Hulsmans H.M.J., Speyer I et al. Efficacy of methotrexate treatment in patients with probable rheumatoid arthritis: A double-blind, randomized, placebo-controlled trial. Arthritis Rheum 2007; 56:1424-1432.
Kaarela K, Jantti JK, Lehtinen K. Unclassified early arthritis is often spondyloarthritis. J Rheumatol 2003; 30(6):1393.
Jantti JK, Kaarela K, Lehtinen KE. Seronegative oligoarthritis: a 23-year follow-up study. Clin Rheumatol 2002; 21(5):353-356.
Disclosure of Interest None Declared