Relationship between systemic lupus erythematosus and autoimmune thyroid disease

Abstract

Objective To evaluate the incidence of autoimmune thyroid disease (AITD) in systemic lupus erythematosus (SLE) and examine the correlation between AITD and SLE activity. Methods The study group included 220 SLE patients with the screening of thyroid function (FT3, FT4, TSH) and anti-thyroid autoantibodies (TgAb, TPOAb) were hospitalized into Affiliated Hospital, Jining Medical College between July 2009 and October 2013.The control group included 160 healthy subjects.We compared the prevalence of AITD between SLE patients and normal controls and also the positive rate of anti-thyroid autoantibodies was observed.We also compared the positive rate of anti-thyroid autoantibodies between AITD in SLE and simple SLE group and also analyzed the correlation between two groups of patients and SLE activity (evaluated by the titer of anti-dsDNA, C3, C4, CH50, SLEDAI score). Results Among them, 45 patients suffered from AITD (20.5%). There were hyperthyroidism (n=6, 13.3%) and hypothyroidism (including subclinical hypothyroidism) (n=26, 57.8%), Hashimoto's thyroiditis (n=13, 28.9%). And 74 SLE cases were positive for anti-thyroid autoantibodies.The prevalence of AITD and the positive rate of anti-thyroid autoantibodies in SLE patients (20.5%, 33.6%) were higher than that in normal controls (3.13%, 7.50%)(P 0.05). Conclusions The SLE patients have a great prevalence of AITD and a positive rate of anti-thyroid autoantibodies.Those with anti-thyroid autoantibodies have a higher incidence of AITD and it has nothing to do with SLE activity.It is essential to monitor thyroid function and thyroid autoantibodies during the follow-ups. Key words: Lupus erythematosus, systemic; Thyroiditis autoimmune; Autoantibodies