CST3 and cancer: There were no significant differences in medical history of coronary heart disease and cancer, BMI, the use of oral hypoglycemic drugs, NLR, serum creatine, serum urea, serum cystatin C, serum urine acid, serum β2 hemoglobulin, eGFR, blood glucose, glycated hemoglobin, bicarbonate, and PH value of urine between the derivation cohort and external validation cohort.