Autoimmune Thyroid Disease in Patients with Systemic Lupus Erythematosus: A 7-year Retrospective Study in China.

Background: The study was a retrospective case-controlled study. We aimed to determine the clinical and laboratory features of systemic lupus erythematosus (SLE) and compared the features of autoimmune thyroid disease (AITD) with those of SLE. Materials and Methods: The study included 38 patients with SLE with AITD (SLE-AITD) and 190 age- and gender-matched SLE patients. The distribution of sociodemographic and clinical factors was compared between the SLE-AITD and SLE groups using Chi-square tests for gender and t tests for others. Univariate and multivariate logistic regression models were used to identify factors associated with the prevalence of AITD among SLE patients. Results: In univariate analysis, malar rash, oral ulcers, serositis, anti-double-stranded DNA antibody positivity (anti-dsDNA+), anti-Sjogren's syndrome type A antibodies (SSA), anti-Sjogren's syndrome type B antibodies (SSB), low complement 3 (C3), and low complement 4 (C4) were significantly different between the SLE-AITD and SLE groups. There were no significant differences among other clinical or laboratory features. In multivariate analysis, serositis (adjusted odds ratio [AOR], 3.64; P = 0.00), anti-dsDNA+ (AOR, 0.30; P = 0.01) and low C3 (AOR, 0.30; P = 0.02) were all associated with SLE-AITD. Conclusions: In our study, serositis was a risk factor for AITD, so we propose that AITD should be considered in lupus patients with serositis.