Background Since the 2010 revision of the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) Classification Criteria and the availability of anti-cyclic citrullinated peptide antibody (ACCP) testing, patients newly diagnosed with rheumatoid arthritis (RA) are commonly tested for both rheumatoid factor (RF) and ACCP. Patients with ACCP or RF positivity are reported to have worse clinical and radiographic outcomes; however, the presence of ACCP may confound the effects of RF and vice versa.
Objectives To determine if there were any differences at study baseline in RA patients who were ACCP-positive, RF-positive, doubly positive and doubly negative in terms of demographics, clinical, functional, laboratory features and radiographic erosions in a multi-ethnic cohort of RA patients in a tertiary rheumatology centre in Singapore.
Methods This cross-sectional study was conducted at Tan Tock Seng Hospital in Singapore. 1206 patients fulfilled the ACR 1987 criteria for RA, of whom 475 were excluded due to a lack of both ACCP and RF status. Serum levels of ACCP and RF were analysed for differences in demographics (gender, ethnicity, age, smoking status, disease duration before study entry), clinical activity (Disease Activity Score-28 (DAS-28)), functional status (Health Assessment Questionnaire (HAQ) score), quality of life (Short-Form 36 (SF-36) physical and mental components), haemoglobin levels (Hb), erythrocyte sedimentation rate (ESR), hand radiographic erosions, and the use of prednisolone and disease modifying anti-rheumatic drugs (DMARDs) at study entry.
Results 731 patients were studied of whom 491 were ACCP+RF+, 54 were ACCP+, 82 were RF+ and 104 were doubly negative. Mean disease duration of RA prior to study entry was similar among the groups at 97.8–105.1 months (p=0.971) and mean disease duration before first DMARD was 38.8–42.7 months (p=0.966). 24.4% of the ACCP+RF+ patients were in remission (DAS-28 <2.6) compared to 36.6–39.4% in the other groups (p<0.05). ESR was higher (40.4mm/hour) in the ACCP+RF+ group compared to 30.6–30.9 mm/hour in the others (p<0.05). The use of prednisolone and number of DMARDs was higher in the ACCP+RF+ group (1.40±0.71) compared to the doubly negative group (1.13±0.59) (p<0.05). There were no differences in demographics, radiographic erosions, functional status and quality of life scores.
Conclusions Patients who had dual positivity for ACCP and RF had lower remission rates and required more corticosteroid and DMARD treatment at baseline. However, this did not seem to have an impact on their functional status, quality of life and radiographic erosions. Future prospective studies would be useful to determine if the prognosis of patients with RA are affected by ACCP and RF positivity.
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Kroot EJ, de Jong BA, van Leeuwen MA, et al. The prognostic value of anti-cyclic citrullinated peptide antibody in patients with recent-onset rheumatoid arthritis. Arthritis Res Ther 2005;7:R949–958
Disclosure of Interest None declared