UNDIFFERENTIATED ARTHRITIS IN AN EARLY SYNOVITIS OUTPATIENT-CLINIC

Objective. To describe the features of undifferentiated arthritis in a n early synovitis out-patient clinic. Methods. In a two-year prospecti ve cohort study 320 patients with rheumatic symptoms of less than one year were investigated in an early synovitis out-patient clinic. Besid es the clinical parameters, an intensive laboratory program was perfor med, including routine blood and serum parameters, immunological inves tigations (CRP, IgG, A, M, C3 C4, RF, ANA, DNA, HLA B-27), and a micro biological program to search for reactive arthritis-inducing infection s. Results. 217 patients had inflammatory rheutmatic diseases, ofw who m only 100 (46%) could be given a definite diagnosis, whereas 117 (54% ) were considered as having undifferentiated arthritis (UA). Patients with UA had a mean age of 41 +/- 15 years, the sex-ratio was 1.8:1.0 ( f/m), joint manifestations were oligoarticular in 68%, monarticular in 14%, and polyarticular in 18%. Rheumatoid factor was positive in 17%, HLA-B27 was found in 27%, and 21% of the patients had a history of re cent infection. Follow up over 26 (range 4-38) months of 28 (24%) pati ents with UA revealed complete remission in 15 patients (54%), while 1 0 patients (36%) had further UA with partial remission unchanged activ ity or progressive disease, and only 2 (7%) developed rheumatoid arthr itis (RA) and 1 (4%) was diagnosed as having ankylosing spondylitis. C onclusion. Most patients with early synovitis followed at our clinic r emain unclassified with a good prognosis.