Objectives To describe the diagnostic spectrum, arthritis persistency and clinical outcomes after 2 years in patients with inflammatory arthritis (IA) of less than 16 weeks’ duration.
Methods Data from the Norwegian Very Early Arthritis Clinic, a 2-year longitudinal observational study of adults with IA of ≤16 weeks’ duration, were used. Exclusion criteria were arthritis due to crystal deposits, trauma, osteoarthritis and septic arthritis. In all patients who had any follow-up information (population A), clinical diagnoses and persistency of arthritis were described. For patients with 2-year follow-up (population B), we also studied other clinical outcomes (disease activity, pain, fatigue, functional disability and health-related quality of life).
Results In population A (n=1017) median (25th–75th percentile) duration of joint swelling was 35.0 (13.0–66.5) days, mean (SD) age 45.7 (14.8) years, 55.2% were females and 17.8% anticitrullinated protein antibodies positive. The most common final diagnoses were undifferentiated arthritis (UA) (41.7%), rheumatoid arthritis (RA) (24.1%) and reactive arthritis (18.1%). After 2 years, the arthritis had resolved in 59% of the patients. The remaining 41.0% had persistent disease defined by disease modifying antirheumatic drug (DMARD) use (32.1%) or persistent joint swelling without DMARD use (8.9%). In population B (n=669), all clinical outcomes improved significantly (P<0.001). Baseline joint pain and fatigue were similar across diagnoses.
Conclusions Among 1017 patients with IA of ≤16 weeks’ duration, UA was the most common diagnosis after 2 years, and less than one-fourth were diagnosed with RA. Arthritis resolved without DMARDs in the majority of the patients. All clinical parameters improved significantly over a 2-year course.
- outcomes research
- early rheumatoid arthritis
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Contributors ESN, GHB, TKK, EL and MDM were involved in study design, interpretation of the data and drafting of the work. ESN, GHB, TKK, OB, AJH, HN, CT and MDM contributed to acquisition of the data. ESN conducted statistical analyses. All authors revised the manuscript critically and approved the final version of the manuscript.
Funding This work was supported by The Norwegian Extra Foundation for Health and Rehabilitation through EXTRA funds and the Norwegian Rheumatism Association, as well as the South-Eastern Norway Regional Health Authority.
Competing interests TKK has received fees for speaking and/or consulting from AbbVie, Biogen, BMS, Boehringer Ingelheim, Celltrion, Eli Lilly, Epirus, Janssen, Merck-Serono, MSD, Mundipharma, Novartis, Oktal, Orion Pharma, Hospira/Pfizer, Roche, Sandoz and UCB.
Patient consent Obtained.
Ethics approval Regional Committee for Medical and Health Research Ethics (REC).
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No additional data are available.
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