Background: We hypothesized that the prevalence of low T3 would be increased according to the increase in CKD stage. This study was performed to explore the prevalence in each stage of CKD and relationship with eGFR.
Methods: A total of 2284 cases with normal thyroid-stimulating hormone (TSH) level were enrolled and retrospectively analysed during the recent period, from July 2005 to December 2007.
Results: There was an increasing trend for the population of low T3 according to the increase of a CKD stage (eGFR > or = 90, 8.2%; > or = 60 eGFR < 90, 10.9%; > or = 30 eGFR < 60, 20.8%; > or = 15 eGFR < 30, 60.6%; eGFR < 15, 78.6%). Also, there was positive relationship between eGFR and serum T3 in male, female and total subjects. After adjusting for age and sex, compared with eGFR > or = 60 ml/min/ 1.73 m2, eGFR < 60 ml/min/1.73 m2 was associated with an increased odds of low T3 [odds ratio 2.40 (CI: 1.5315 to 3.1731)]. In multiple regression analysis, eGFR was positively related with T3 (standardized coefficient 0.143, R2 = 0.055, P < 0.001), independent of age and serum albumin.
Conclusion: This study showed that low T3 syndrome was highly prevalent in CKD and was a remarkable finding in early CKD. Furthermore, serum T3 levels were associated with severity of CKD even in the normal TSH level.