THE PROGNOSIS OF RHEUMATOID-ARTHRITIS AND UNDIFFERENTIATED POLYARTHRITIS SYNDROME IN THE CLINIC - A STUDY OF 1141 PATIENTS

Objective. To determine the prognosis of undifferentiated polyarthriti s syndrome in the clinic compared with rheumatoid arthritis (RA). Meth ods. We identified consecutive patients seen within the first 2 years of disease (and further subset into 6-month groups) diagnosed as havin g either RA or undifferentiated polyarthritis syndrome at the first cl inic visit. Undifferentiated polyarthritis syndrome was characterized by clinical presentation, laboratory data, and American College of Rhe umatology (ACR) 1958 and 1987 RA criteria. Followup evaluations were d one to determine change in diagnosis, resolution of symptoms, and clin ical remission of RA. Results. Undifferentiated polyarthritis syndrome was more common in the clinic than RA (638 vs 503). Of patients with RA 7.6% were symptom free an average of 6.9 years after the first clin ic visit. For those with disease onset between 0-6 months and 0-2 year s, complete resolution of undifferentiated polyarthritis syndrome occu rred in 57.9 and 53.9% of cases, including 46.1 and 35.6% meeting ACR 1987 criteria for RA. Latex positivity was the strongest predictor of failure to resolve subsequently (25.0 and 29.2% resolution) and the be st predictor of development of RA (41.7 and 43.1%). Conclusions. Nonrh eumatoid undifferentiated polyarthritis syndrome is more common in the clinic than RA. Undifferentiated polyarthritis syndrome resolves in m ore than half the cases, while RA remits in 7.6%. Finally, resolution of RA criteria positive undifferentiated polyarthritis syndrome occurs predominantly in those who are seronegative.