Pro: Thresholds to define chronic kidney disease should not be age-dependent

Abstract

Current thresholds to define chronic kidney disease (CKD) are essentially based on two measures, estimated GFR (eGFR) and albuminuria. The first two stages (stage 1 and 2) are mainly defined by the presence of abnormal albuminuria (>30 mg/g creatinine). Conversely, overt CKD (stages 3–5) is defined by an eGFR 30 mg/g creatinine) can also be considered adequate cut-off values for definition of CKD in advanced age. To examine the relationship between age and kidney measures for CKD definition, two issues should be addressed. The first is represented by the assessment of kidney function in healthy subjects in function of age to establish whether eGFR below the threshold value (<60 mL/min/1.73 m 2 )i s ap rocess of physiologic senescence or a sign of renal pathology. The second one concerns the evaluation of the interaction between age and eGFR/albuminuria thresholds on the risk of death and end-stage renal disease (ESRD). We examined the main studies characterized by high number of participants and/or long-term follow-up that analysed the whole age spectrum including very elderly subjects, in different study settings, i.e. general population, high-risk patients and CKD patients, including those under nephrology care.