Comparison of long term outcome of patients with rheumatoid arthritis presenting with undifferentiated arthritis or with rheumatoid arthritis: an observational cohort study
- 1Department of Rheumatology, Leiden University Medical Centre, Leiden, The Netherlands
- 2Department of Medical Statistics, Leiden University Medical Centre, Leiden, The Netherlands
- Correspondence to:
Professor T W J Huizinga
Department of Rheumatology, Leiden University Medical Centre, PO Box 9600, 2300 RC, Leiden, The Netherlands;
- Accepted 15 May 2005
- Published Online First 18 May 2005
Background: The outcome of undifferentiated arthritis (UA) ranges from remission to rheumatoid arthritis (RA) fulfilling the American College of Rheumatology (ACR) classification criteria.
Objectives: To report the outcome of UA after 1 year of follow up and compare the disease course of patients who presented with UA, but evolved into RA within 1 year (UA-RA group), with that of patients who presented with RA fulfilling the ACR criteria (RA-RA group).
Methods: The diagnosis of 330 patients who presented with UA was recorded at 1 year. The UA-RA and RA-RA groups were then followed up for 3 more years. Outcome measurements were radiographic progression, disease activity, and functional capacity.
Results: From 330 patients who were diagnosed UA, 91 had evolved into RA at 1 year; 62 patients had presented with RA. No significant differences were detected between the UA-RA and RA-RA groups in median Sharp/van der Heijde score at baseline, radiographic progression rates, disease activity, and functional capacity. However, significantly more disease modifying antirheumatic drugs were prescribed in the RA-RA group.
Conclusion: The disease outcome of patients who present with UA that evolves into RA within 1 year is the same as that of patients who present with RA as measured by radiographic progression, disease activity, and functional capacity.
- ACR, American College of Rheumatology
- CCP, cyclic citrullinated peptide
- CRP, C reactive protein
- DAS, Disease Activity Score
- DMARD, disease modifying antirheumatic drug
- EAC, Early Arthritis Clinic
- ESR, erythrocyte sedimentation rate
- HAQ, Health Assessment Questionnaire
- RA, rheumatoid arthritis
- RF, rheumatoid factor
- UA, undifferentiated arthritis
- undifferentiated arthritis
- rheumatoid arthritis
- radiographic progression
- joint damage
- disease outcome
↵* Drs J van Aken and H van Dongen contributed equally to this work
Published Online First 18 May 2005
Competing interest: none declared
Ethics approval and patient consent: The “Commissie Medische Ethiek” of the Leiden University Medical Centre approved the protocol of the Leiden Early Arthritis Clinic (EAC). All the patients who were included in the Leiden EAC signed an informed consent.