ALB and chronic kidney disease: CKD is defined according to the KDIGO Clinical Practice Guideline for the Evaluation and Management of CKD (2012), i.e., a decreased GFR of <60 mL/min/1.73 m2, an albumin creatinine ratio (ACR) of >30 mg/g (>3 mg/mmol) or a history of kidney transplantation (estimated according to the CKD-EPI equation).