Association between Hypothyroidism and Chronic Kidney Disease in Korean Adults: A Study Based on the Sixth Korea National Health and Nutrition Examination Survey (KNHANES VI), 2013–2015

ABSTRACT

Background@#Previous studies suggested the correlation between thyroid and kidney functions, especially the high prevalence of hypothyroidism in chronic kidney disease. This study aimed to evaluate the influence of hypothyroidism on kidney function in Korean adults by using data from a representative nationwide survey. @*Methods@#This was a cross-sectional study composed of 5,250 individuals aged ≥19 years who were enrolled in the sixth Korea National Health and Nutrition Examination Survey. The participants were classified into three groups of patients with euthyroidism, subclinical hypothyroidism, and overt hypothyroidism according to thyroid function. Chronic kidney disease was defined as having a decreased estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m2. Univariate and multivariate logistic regression analyses were used to evaluate the prevalence and adjusted odds ratio (aOR) of chronic kidney disease. @*Results@#Compared with the euthyroidism group, the subclinical and overt hypothyroidism groups showed higher prevalence rates of chronic kidney disease in both sexes. This tendency was significant in the elderly people aged ≥65 years. In the multivariate logistic regression analysis, the subclinical hypothyroidism group did not show a significant difference (adjusted odds ratio [aOR], 1.78; 95% confidence interval [CI], 0.82–3.87) from the euthyroidism group. In the overt hypothyroidism group, the aOR of chronic kidney disease was significantly higher (aOR, 5.90; 95% CI, 1.73– 20.15) than that in the euthyroidism group. @*Conclusion@#Overt hypothyroidism was associated with decreased eGFR and may be considered as an independent risk factor of chronic kidney disease.