NHANES study. Strikingly, only 2.0% of these high risk patients self-reported a history of kidney disease. These consistent findings over the past decade underscore the lack of recognition and education regarding CKD and the missed opportunities to better manage, prevent, and reduce CKD’s associated premature and increased comorbidties, mortality, and high healthcare costs. Stratification of CKD into 5 stages focuses the clinician on CKD management aspects. The metabolic abnormalities of CKD evolve in a fairly well established pattern. Anemia of CKD and CKD-Mineral and Bone Disorder (CKD-MBD) often begin during Stage 3. Hypertension is aggravated in CKD Stages 3–5 and acid-base balance, dyslipidemia, and glucose homeostasis become deranged later. During Stages 3–5, reductions in medication dosages may be required because of a lower eGFR. The disease domains of HTN, proteinuria, and hyperlipidemia may appear at any stage and therapy must be targeted to specific levels. Lastly, screening for metabolic complications of CKD is typically not recommended in persons with eGFR >60 mL/min/1.73 m2 and no albuminuria, unless a genetic disorder with a high degree of penetrance is present (autosomal dominant polycystic kidney disease). The development of CKD multiplies the mortality risk associated with CVD, particularly in CKD Stages 4 and 5. CKD increases CVD morbidity and mortality risks in diabetics by 2- to 4-fold and 7 in patients with HTN and diabetes by 4- to 8-fold. Further, CKD-attributable CVD risk increases rapidly through CKD Stages 3–5 by several-fold. At-Risk Groups CKD carries a 3-fold higher risk of death. Therefore, clinical risk factors for the initiation and/or progression of CKD should be ascertained during routine healthcare encounters and periodically, thereafter. Individuals at increased risk for CKD must be tested for kidney damage and have their eGFRs evaluated more frequently. In addition, aggressive risk factor reduction should be carried out in individuals at increased risk for CKD even when CKD is not clinically apparent. A CKD risk factor classification, based on a cardiovascular scheme follows (see Table, p. 9). Hypertension (prevalence 74.5 million) and diabetes (prevalence 23.6 million) are the two most important CKD risk factors. Overall, diabetes is prevalent in 44% of the ESRD population and in HTN 28%. Together, these two disorders constitute 72% of the causes of ESRD. Recently, insulin resistance, obesity, and the metabolic syndrome have been implicated as risk factors. A family history of kidney disease is a risk factor for CKD. Nearly 24% of ESRD patients have an afflicted first-degree relative, an association that is much stronger in African Americans than whites. Other CKD risk factors include the following: a prior history of AKI/ARF, urinary tract obstruction, stones, reduced kidney mass (solitary kidney), nephrotoxins (analgesics, aminoglycosides, amphotericin, radiocontrast), autoimmunity (SLE), low birth weight, preeclampsia, sociodemographics (older age, male gender, reduced access to healthcare, low income/education level, hazardous chemical or environmental exposures), and certain ethnicities: African American, Native American, Hispanic, and Asian. Acute Kidney Injury (AKI)/Acute Renal Failure (ARF) The term ARF is being increasingly supplanted by the term AKI, but precise and consensus-based definitions of AKI have only recently been introduced. AKI is common and occurs at a rate of 522 cases/100,000 pt-yr. Thus far, AKI staging systems that define renal risk, injury, and failure have not consistently predicted renal or morbid outcomes due to select patient-specific demographics, preexisting CKD and comorbidities (see TABLE, P. 8). Such systems require further refinement. AKI often complicates CKD, particularly in Stages 3–5. Persons with or without preexistent kidney disease may incur permanent decrements in kidney function after single or repeated episodes of AKI/ARF. The optimal method of establishing CKD is by examining medical records; renal imaging is the next best method, eg, kidney ultrasonography (US) or CT scan. By US, normal, adult kidney sizes are 10–12 cm in the sagittal plane; however, size discrepancies up to 37% may be found. AKI represents a substantial risk factor for progressive CKD. A single episode of AKI may generate a steeper decline in renal function than normally expected from aging alone. Therefore, patients who develop severe AKI or recover slowly from AKI must be closely monitored, even when the eGFR returns to baseline. Rapid recovery of AKI (6 h 2 Injury SCr of ≥2.0–3.0-fold 12 h 3 Failure SCr of ≥0.3 mg/dL or >3-fold from baseline SCr ≥4.0 mg/dL with acute ≥0.5 mg/dL 5.5 mEq/L), oliguria, relative hypotension, or a substantial GFR reduction occurs, these agents should generally be continued. Progression of Chronic Kidney Disease (CKD) Fortunately, most patients do not progress from CKD Stage 3 to 5, but ~17% of CKD Stage 4 patients will progress to Stage 5 and ~1% of CKD Stage 3 patients will. However, the transition to CKD Stage 4 is often insidious and under-recognized. Importantly, this transition represents a “clinical event” similar to a stroke or acute myocardial infarction because CKD Stage 4 is marked by a major increase in cardiovascular mortality and progression to CKD Stage 5. During CKD Stage 4, death is a competing risk for