Prevalence of thyroid dysfunctions and thyroid autoantibodies in Thai patients with systemic lupus erythematosus: An age‐ and sex‐matched controlled study

Background/Objective To determine the prevalence of thyroid dysfunctions and thyroid autoantibodies in Thai systemic lupus erythematosus (SLE) patients, and compare them with age‐ and sex‐matched healthy controls (HCs). Associations between thyroid dysfunctions and SLE disease activity, and associated factors for thyroid dysfunctions in SLE also were determined. Method One hundred SLE patients, without apparent clinical thyroid disease, attended the Rheumatology Clinic between November 2021 and October 2022, were enrolled into this study. HCs were matched to SLE cases by age and sex (ratio of 1:1). Clinical manifestations, SLE disease activity and medication received were collected in all SLE patients. Thyroid function tests and thyroid autoantibodies (anti‐thyroglobulin: anti‐TG and anti‐thyroid peroxidase: anti‐TPO) were collected from all participants. Results When compared with HCs, SLE patients had higher prevalence of thyroid dysfunctions, hypothyroidism and euthyroid sick syndrome (28% vs. 7%, p < .001, and 12% vs. 2%, p = .010, and 6% vs. 0%, p = .013, respectively). Prevalence of isolated hypothyroxinemia was higher numerically in SLE patients (9% vs. 3%, p = .074). Prevalence of anti‐TG or anti‐TPO was no different between SLE patients and HCs (16% vs. 18%, p = .707). There was no association between SLE disease activity and abnormal thyroid functions or thyroid autoantibodies. Family history of thyroid disease and prednisolone use (>10 mg/day) were associated factors for thyroid abnormalities with adjusted OR (95% CI) of 6.13 (1.58–23.75), p = .009 and 4.00 (1.37–11.70), p = .011, respectively. Conclusion Thyroid dysfunctions were more prevalent in SLE patients. Family history of thyroid disease and prednisolone use (>10 mg/day) were independent associated factors of thyroid abnormalities.