Conceptual model of CKD: applications and implications.

The conceptual model of chronic kidney disease (CKD) was developed by the National Kidney Foundation's Kidney Disease Quality Outcome Initiative (NKF-KDOQI) in 2002 and subsequently revised and adopted by an international consensus under the auspices of KDIGO (Kidney Disease: Improving Global Outcomes) in 2005. This model includes concepts of definition, staging, outcomes, and treatment, as well as risk factors for the development, progression, and complications of CKD. Treatments are available for patients with risk factors and for each stage of CKD; these include slowing the progression of kidney disease, preventing and treating the complications of decreased glomerular filtration rate, and reducing cardiovascular disease risk factors and treating cardiovascular disease. In principle, measures to improve the prevention, detection, and treatment could reduce adverse outcomes, improve the quality of life, and prolong the survival of individuals with CKD. The conceptual model for CKD is now being applied to a public health approach for the prevention of the development, progression, and complications of CKD. Primary prevention is defined as prevention of CKD; secondary and tertiary prevention are defined as improving outcomes of patients with CKD stages 1 to 4 and kidney failure (CKD stage 5), respectively. The conceptual model has also fostered debate about important questions: Is CKD a disease or a cardiovascular disease risk-factor condition? Do all patients with CKD need to be referred to a nephrologist? What does CKD care include? Should the classification be modified to include cause of disease and prognosis? Can CKD evolve from acute kidney disease, and is CKD reversible? Is albuminuria a manifestation of a kidney disease or systemic endothelial dysfunction? Is the age-related decrease in glomerular filtration rate normal or abnormal, and should we change the definition of CKD in the elderly? A combination of immediate action, data gathering, and research to establish the efficacy, effectiveness, and costs related to CKD are needed to respond to CKD as a public health problem.