One hundred sixty-one MCTD patients were evaluated retrospectively at the diagnosis and in 2008. They were classified, at the diagnosis, according to the 3 classification criteria of MCTD (Sharp, Alarc¨®n-Segovia, and Kasukawa) and reclassified in 2008 according to their evolution. Statistical analyses were performed to find out predictors (clinical features and autoantibodies) of evolution into other CTDs.
After a mean of 7.9 years of disease, 57.9 % of patients still satisfied MCTD classification criteria of Kasukawa; 17.3 % evolved into systemic sclerosis, 9.1 % into systemic lupus erythematosus, 2.5 % into rheumatoid arthritis, 11.5 % was reclassified as affected by undifferentiated connective tissue disease, and 1.7 % as suffering from overlap syndrome. Kasukawa's criteria were more sensitive (75 % ) in comparison to those of Alarc¨®n-Segovia (73 % ) and Sharp (42 % ). The presence of anti-DNA antibodies (P = 0.012) was associated with evolution into systemic lupus erythematosus; hypomotility or dilation of esophagus (P < 0.001); and sclerodactyly (P = 0.034) with evolution into systemic sclerosis.
MCTD is a distinct clinical entity but it is evident that a subgroup of patients may evolve into another CTD during disease progression. Initial clinical features and autoantibodies can be useful to predict disease evolution.