INTRODUCTION
Thyroid and renal function have well-documented associations. Thyroid hormones (TH) are required for kidney growth and for development and maintenance of water and electrolyte balance. Thyroid dysfunction affects kidney function, and renal failure affects thyroid hormone metabolism in the peripheries as well as the hypothalamic-pituitary-thyroid axis (1). TH are necessary for the kidney to complete its functional growth and for the development, preservation and maintenance of glomerular function (2). Overt hypothyroidism in particular has been linked to a reduction in glomerular filtration rate (GFR) and renal blood flow (RBF) (3). Cases of acute kidney injury (AKI) due to severe hypothyroidism have been reported in the literature. Since AKI due to severe hypothyroidism is rare, the number of cases is insufficient for publication beyond case series (4). The glomerular function is more impaired than tubular function during severe hypothyroidism. In severe hypothyroidism, a reduction in RBF has been documented, which is most likely due to the overall hypodynamic circulation, reduced cardiac output due to myocardial impairment, sinus bradycardia, and the reduced inotropy and chronotropy due to lower levels of TH (5). However, the risk factors of AKI due to severe hypothyroidism has not been fully elucidated. This study aimed to investigate the factors that affect the development of AKI in patients with severe hypothyroidism.