Definition and classification of CKD: the debate should be about patient prognosis--a position statement from KDOQI and KDIGO.

m g e 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 AQ:1 n 2002 the National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative KDOQI) published a guideline on chronic kidey disease (CKD) covering evaluation, classifiation, and stratification of risk. The workgroup eveloping this guideline provided a new concepual framework for a diagnosis of CKD indepenent of cause, and developed a classification cheme of kidney disease severity based on the evel of glomerular filtration rate (GFR). Before his new system for defining and staging CKD as developed, vague and variable terminology, uch as “chronic renal failure,” “chronic renal nsufficiency,” “pre-dialysis,” and “pre-endtage renal disease” prevented the use of a comon and precise language. The new system also epresented a significant conceptual change, since idney disease historically had been categorized ainly by cause. The definition is based on 3 omponents: (1) an anatomical or structural comonent (markers of kidney damage, including lbuminuria), (2) a functional component (based n GFR), and (3) a temporal component (at least months’ duration of structural and/or funcional alterations). The diagnosis of CKD relies n markers of kidney damage and/or a reduction n GFR. Stages 1 and 2 define conditions of idney damage in the presence of a GFR of at east 90 mL/min/1.73 m or 60 to 89 mL/min/ .73 m, respectively, and stages 3 to 5 define onditions of moderately and severely reduced FR irrespective of markers of kidney damage Table 1). The impact that this classification system has ad in only 6 years on the awareness of CKD in ndividuals and populations, on research activiies, research support, and public health policy as been tremendous. There has been an exponenial increase in the amount of research performed n patients with kidney disease not receiving ong-term dialysis therapy since the guidelines ere released, and the common definition of KD has facilitated comparisons between studes. Thus, this new diagnostic classification of KD has likely been one of the most profound onceptual developments in the history of nehrology.