Autoimmune thyroid disease in Colombian patients with systemic lupus erythematosus

Abstract

OBJECTIVES: To determine the prevalence and the predictive factors of autoimmune hypothyroidism (AH) within a systemic lupus erythematosus (SLE) cohort and to analyse the current information concerning the prevalence and impact of autoimmune thyroid disease (AITD) and thyroid autoimmunity in patients with SLE.

METHODS: A total of 376 patients with SLE were assessed for the presence of the following: (i) confirmed AH, (ii) positive thy-roperoxidase/thyroglobulin antibodies [TPOAb/TgAb] without hypothyroidism, (iii) nonautoimmune hypothyroidism and (iv) SLE patients with neither. Multivariate analysis and a classification and regression tree model were used to analyse data. The current information was discussed through a systematic literature review (SLR).

RESULTS: In our cohort, the prevalence of confirmed AH was 12%. However, in euthyroid patients with SLE, TPOAb and TgAb were observed in 21% and 10%, respectively. Patients with confirmed AH were significantly older and had later age at onset of the disease. Smoking (adjusted odds ratio (AOR) 6·93, 95% CI 1·98-28·54, P = 0·004), Sjögren's Syndrome (SS) (AOR 23·2, 95% CI 1·89-359·53, P = 0·015) and positivity for anticyclic citrullinated peptide (anti-CCP) (AOR 10·35, 95% CI 1·04-121·26, P = 0·047) were associated with AH-SLE, regardless of gender and duration of the disease. Smoking and SS were confirmed as predictors of AH-SLE. In the SLR, the prevalence of AITD ranged from 1% to 60%. The factors associated with this polyautoimmunity were female gender, older age, smoking, certain autoantibodies, SS, and cutaneous and articular involvement.

CONCLUSIONS: AITD is frequent in SLE and does not affect the severity of SLE. Identified risk factors will assist clinicians in the search for AITD. Our results encourage smoke-free policies in patients with SLE.