Undifferentiated connective tissue disease (UCTD) refers to a cluster of systemic disorders characterized by a simple clinical and autoantibody profile. Previously, we had described a series of 91 patients with UCTD who were followed at our unit for a minimum period of one year; here we report the extended followup of these patients.
Of the original 91 patients, 8 were lost to followup; the remaining 83, with a minimum followup of 5 years, were included in our analysis.
During the followup 18 patients developed systemic lupus erythematosus (SLE) and one developed Sjögren's syndrome within a mean period of 54 months after the onset of the disease (range 17-96 mo). On analysis the 18 patients with SLE showed a clinical profile similar to cohorts reported in the literature. In one patient the evolution to SLE occurred during puerperium, but no other triggering factors were observed in our series. The presence of anticardiolipin antibodies and of multiple antibody specificities was significantly correlated with the development of SLE (p < 0.05).
This analysis confirms the findings of our one year followup study that UCTD comprises a distinct group of mild diseases and that the rate of evolution to defined connective tissue diseases is higher during the first years after its onset. Patients who maintain an undifferentiated profile during the followup seem to run a decreasing risk of developing a defined CTD.