Early undifferentiated connective tissue disease (CTD). VI. An inception cohort after 10 years: disease remissions and changes in diagnoses in well established and undifferentiated CTD.

OBJECTIVE: (1) To review the diagnoses after 10 years in patients who were identified within 12 months of the onset of well established and undifferentiated connective tissue diseases (CTD). (2) To examine the death rates and disease remissions in these patients.

METHODS: This inception cohort of 410 patients had less than one year of signs and/or symptoms of CTD. Diagnoses of rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and poly/dermatomyositis (PM/DM) were made in 197 patients using accepted diagnostic and classification criteria. Diagnoses of undifferentiated CTD were made in 213 patients. These latter patients were placed in 3 categories: isolated Raynaud's phenomenon (RP), unexplained polyarthritis (UPA), and undifferentiated CTD (UCTD), defined as meeting at least 3 of 11 specific manifestations of CTD. The diagnoses and remissions in all patients after 10 years were determined.

RESULTS: Patients with well established CTD tended to remain with the original diagnosis. The 10 year survival was at least 87% in all diagnostic categories, with the exception of SSc, in which it was 56%. The progression of UPA to RA occurred infrequently. The presence of antinuclear antibodies suggested that UPA may develop additional symptoms and/or a specific diagnosis, and RP in these patients increased the likelihood of progressing to UCTD or a specific well established CTD. Ten percent of patients with RP progressed to SSc. In patients with UCTD, joint pain/tenderness and swelling counts were associated with progression to other diagnoses including RA, while either serositis, malar rash, or discoid lupus suggested the eventual diagnosis of SLE.

CONCLUSION: The survival of patients with SSc was poor, with most dying early in the course of their disease. Remissions were seen in all groups of patients except SSc. The remissions were sometimes transient in SLE. Undifferentiated disease at initial examination within 12 months of onset usually remains undifferentiated.