Albuminuria is an independent risk factor of T4 elevation in chronic kidney disease

This study was to explore the association between thyroid dysfunction and albuminuria. 581 cases with chronic kidney disease (CKD) were included in this study. The clinical characteristics consisted of sex, age, serum creatinine, urinary albumin-to-creatinine ratio (ACR), thyroid function were recorded. Estimated glomerular filtration rate (eGFR) was calculated by CKD-EPI four-level race equation. Prevalence of different thyroid diseases was calculated by chi-square test. Levels of thyroid hormone were compared among different albuminuria groups by Kruskal-Wallis test. Spearman's correlation was used to assess the association between albuminuria and thyroid hormone. Our study showed that total T4 and free T4 were significantly different among ACR < 30 mg/g, 30-300 mg/g and >300 mg/g (P < 0.001 and =0.007, respectively). Positive correlation between T4 (total T4 and free T4) and albuminuria was evaluated by correlation analysis (P = 0.001 and <0.001, respectively). Albuminuria was an independent influence factor of T4 after adjustment for age, sex, serum creatinine, albumin, hs-CRP, smoking status, systolic blood pressure, diabetes mellitus, medication use for diabetes mellitus, eGFR, LDL-cholesterol, triglycerides, hypertension, and medication use for hypercholesterinemia. In conclusion, T4 was positively correlated with albuminuria, and it was completely not consistent with our anticipation. Further study is needed to elucidate the causation association between albuminuria and T4.