Chronic kidney disease (CKD) is defined as kidney damage lasting for more than 3 months characterized by structural or functional abnormalities of the kidney, with or without decreased glomerular filtration rate (GFR). CKD has been subdivided into six stages depending on the estimated GFR (eGFR) and degree of proteinuria: CKD stage 1 is eGFR greater than 90 ml/min (per 1.73 m2) with other evidence of renal disease; CKD stage 2 is eGFR 60 to 89 ml/min, with other evidence of renal disease; CKD stage 3a is eGFR 45 to 59 ml/min; CKD stage 3b is eGFR 30 to 44 ml/min; CKD stage 4 is eGFR 15 to 29 ml/min; and CKD stage 5 is eGFR less than 15 ml/min. At each stage the CKD is further categorized according to the degree of proteinuria based on the albumin:creatinine ratio (ACR), from A1 (no increase in protein excretion) to A3 (severe proteinuria). The eGFR is least accurate when the serum creatinine is within or near the normal range. Mild CKD is common, with about 10% of the population of the United States of America having CKD stage 1, 2, or 3 (combined), but advanced CKD is relatively rare (about 0.2% are receiving renal replacement therapy). Patients with CKD stage 1, 2, or 3 are at relatively low risk of progressing to require renal replacement therapy, but are at high risk of death from cardiovascular disease. This chapter discusses the definition, aetiology, and pathophysiology of CKD, followed by sections on the prevention of progression, medical management of the consequences of CKD (including diet, CKD mineral and bone disorders, advanced hyperparathyroidism, and anaemia), and preparation for renal replacement therapy or conservative management of uraemia.
Predictors of acute renal failure requiring renal replacement therapy post cardiac surgery in patients with preoperatively normal renal function
