Areas under the ROC curves of CKD-EPI-creatinine , CKD-EPI-cystatin C and CKD-EPI-creatinine-cystatin C equations for all-cause mortality were 0.604 ( 95 % CI 0.561-0 .647 ) , 0.606 ( 95 % CI 0.563-0 .649 ; p = 0.963 ) and 0.606 ( 95 % CI 0.563-0 .649 ; p = 0.894 ) respectively .