[2009] [OP-0051] MAY AUTOIMMUNE THYROIDITIS REPRESENT A CANDIDATE RISK FACTOR FOR EVOLUTION OF UNDIFFERENTIATED CONNECTIVE TISSUE DISEASE? RESULTS FROM A PRELIMINARY RETROSPECTIVE CROSS-SECTIONAL STUDY

M. Fotinidi, M. Govoni, S. Bernardi, S. Volpinari, N. Rizzo, F. Trotta Department of Rheumatology, S.Anna Hospital, Ferrara, Italy

Background: Autoimmune thyroiditis (AIT) is the most common of all autoimmune diseases affecting approximately 1.5% of the population, and it is frequently observed in the context of other non-organ specific systemic autoimmune illness including Undifferentiated Connective tissue diseases (UCTD). Its role in conditioning the evolution from UCTD towards a defined CTD or an other disease has not been established yet.
Objectives: to establish the prevalence of AIT in a large cohort of UCTD; to verify clinical and serological association; to ascertain its role as a potential risk factor for progression towards a defined connective tissue disease (CTD).
Methods: All patients fulfilling criteria for UCTD proposed by Mosca and Bombardieri (Clinical Exp Rheumatol, 1999), consecutively observed at our institution, between 1984-2007, were retrospectively analyzed by using information from their clinical charts and dedicated database. Diagnosis of AIT was assessed on the basis of hormonal status, detection of organ-specific autoantibodies (Anti-TPO and Anti-TG), ultrasound findings, and, when available, on the result of cytology obtained by fine needle aspiration. The presence of serum autoantibodies, diffuse thyroid hypoechogenicity and goiter was deemed as indicative of AIT.
Results: 334 patients (321 F, 13 M) satisfying criteria for UCTD were retrieved. Of them,126 were excluded from the study because of short follow-up (less than 3 years). 208 patients (198 F, 10 M) with an average follow up period of 6.6 years were judged eligible for the study purpose.
These patients had an actual mean age of 53,20±14,90 years (range 18-87), and a mean age at disease onset of 44,62±14,27. An AIT was found in 54 patients (25,96%), 53 F (98,10%) and 1 M (1,90%). In the subgroup with AIT, 6 patients (11.1%) presented an evolution of their clinical picture: 1 patient (1,85%) developed an undifferentiated oligoarthritis, and 5 patients (9,25%) manifested lupus-related signs or symptoms without reaching the 4-ACR classification criteria for Systemic Lupus Erythematosus (SLE)(i.e. oligo-lupus).In the subgroup without history or signs of AIT, including 145 F (94,1%) and 9 M (5,8%), 8 out of them (5,19%) progressed towards a defined disease. 3 patients developed SLE, 3 evolved in Rheumatoid arthritis, 1 developed an undifferentiated oligoarthritis and 1 presented a localized scleroderma (morphea) in the lower limbs. On average, the elapsing time of progression towards an other disease calculated from the disease onset, was 79,5 months (ranging from 28 to 252), within 3-5 years in the majority of patients. No significant clinical and serological differences were observed between the 2 groups
Conclusion: The pevalence of AIT was significatively higher (25.9%) than what has been reported in previous studies and in general population. This preliminary retrospective cross-sectional study indicate that UCTD with AIT showed a more frequent (although not statistically significant) evolution towards a defined CTD than UCTD without AIT (11.1% vs 5.19%;p =0.239),regardless of other clinical and serological differences. This information should prompt further investigations to confirm this trend analyzing, in a prospective study, incident cases of AIT in the context of new onset UCTD.
Disclosure of Interest: None declared

Ann Rheum Dis 2009;68(Suppl3):85

Abstract Session: Hot spots in rheumatic disease spectrum