APOB and chronic kidney disease: Serum apoB/A-I ratios may not be helpful to predict CAC in participants with mild RI (90–60 mL/min/1.73 m2 of eGFR), although these participants did not have CKD, which is defined as impaired kidney function (less than 60 mL/min/1.73 m2 of eGFR) or evidence of kidney damage.