Patients with seronegative RA have more inflammatory activity compared with patients with seropositive RA in an inception cohort of DMARD-naïve patients classified according to the 2010 ACR/EULAR criteria.
OBJECTIVE
To compare the presentation of seropositive and seronegative early rheumatoid arthritis (RA) in disease-modifying antirheumatic drug (DMARD)-naïve patients classified according to the 2010 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) criteria.


METHODS
All patients had symptom duration from first swollen joint <2 years and were DMARD naïve with an indication for DMARD treatment. Patients were stratified as seropositive (positive rheumatoid factor (RF)+ and/or anticitrullinated peptide antibody (ACPA)+) or seronegative (RF- and ACPA-), and disease characteristics were compared between groups.


RESULTS
A total of 234 patients were included, and 36 (15.4%) were seronegative. Ultrasonography (US) scores for joints (median 55 vs 25, p<0.001) and tendons (median 3 vs 0, p<0.001), number of swollen joints (median 17 vs 8, p<0.001), disease activity score (DAS; mean 3.9 vs 3.4, p=0.03) and physician global assessment (mean 49.1 vs 38.9, p=0.006) were significantly higher in seronegative patients compared with seropositive. Total van der Heijde-modified Sharp score, Richie Articular Index and patient-reported outcome measures were similar between groups.


CONCLUSIONS
Seronegative patients had higher levels of inflammation, assessed both clinically and by US, than seropositive patients. These differences may reflect the high number of involved joints required for seronegative patients to fulfil the 2010 ACR/EULAR classification criteria for RA.


BACKGROUND
NCT01205854; Pre-results.
Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
Lena Bugge
LB
Nordberg
Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
Siri
S
Lillegraven
Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
Elisabeth
E
Lie
Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
Anna-Birgitte
AB
Aga
Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
Inge Christoffer
IC
Olsen
Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
Hilde Berner
HB
Hammer
Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
Till
T
Uhlig
Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.|Department of Rheumatology, Haukeland University Hospital, Bergen, Norway.
Maria Karolina
MK
Jonsson
Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.|Leiden University Medical Center, Leiden, Netherlands.
Désirée
http://orcid.org/0000-0002-5781-158X
D
van der Heijde
Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
Tore K
TK
Kvien
Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
Espen Andre
EA
Haavardsholm
D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000276:immunology* / Q000503:physiopathology; D001323:Autoantibodies / Q000276:immunology*; D016022:Case-Control Studies; D033023:Foot Joints / Q000000981:diagnostic imaging / Q000503:physiopathology; D050823:Hand Joints / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology*; D012217:Rheumatoid Factor / Q000276:immunology*; D012720:Severity of Illness Index; D014463:Ultrasonography; D018608:Ultrasonography, Doppler
D018501:Antirheumatic Agents; D001323:Autoantibodies; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D012217:Rheumatoid Factor
Ant-CCP; Early Rheumatoid Arthritis; Rheumatoid Arthritis; Rheumatoid Factor