In order to explore the association of thyroid function with DKD, we divided the patients into four groups according to the quartiles of FT3 (<4.38, 4.38–4.73, 4.73–5.12 and ≥5.12pmol/L) and FT4 (<14.84, 14.84–16.13, 16.13–17.66 and ≥17.66 pmol/L) and divided two groups based on TSH (<2.5 and ≥2.50 mIU/L) and TPO-Ab levels (<78 U/mL, ≥78U/ml), respectively. Here, TPO is linked to diabetic kidney disease.