Thyroid dysfunction risk in systemic lupus erythematosus: a systematic review of case-control studies.

OBJECTIVES: This study investigated the prevalence of thyroid dysfunction-including clinical and subclinical hyperthyroidism, clinical and subclinical hypothyroidism, and euthyroid sick syndrome (ESS)-and its associated risk factors in patients with systemic lupus erythematosus (SLE) through case-control studies and meta-analysis. MATERIALS AND METHODS: The prevalence of thyroid dysfunction in SLE patients was first examined in two independent cohorts (Luzhou and Enshi). A meta-analysis was subsequently conducted using studies identified from PubMed and other databases to estimate the global prevalence of thyroid dysfunction among SLE patients. Factors associated with thyroid dysfunction in SLE were analyzed within the two cohorts, and meta-analysis was further employed to synthesize evidence on these associations. RESULTS: The prevalence of all thyroid dysfunction subtypes was higher in SLE patients than in healthy controls. Meta-analysis confirmed that, at a global level, SLE patients had a higher prevalence of clinical hypothyroidism, subclinical hyperthyroidism, and ESS compared with healthy controls. Meta-analysis also identified significant associations between clinical hypothyroidism and renal involvement (P = 0.017) as well as low FT3 levels (P < 0.001). ESS was significantly associated with low C3 (P < 0.001) and low FT3 levels (P = 0.007). CONCLUSIONS: Thyroid dysfunction is prevalent among SLE patients worldwide. Severe renal involvement and decreased FT3 levels indicate an increased risk of clinical hypothyroidism in SLE, while reduced FT3 and C3 levels are associated with a higher risk of ESS.