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KEY CONCEPTS
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The stage of chronic kidney disease (CKD) should be determined for all individuals based on the level of kidney function, independent of etiology, in accordance with the Kidney Disease: Improving Global Outcomes (KDIGO) classification system.
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Persistent proteinuria indicates the presence of CKD and is associated with mortality and risk of end-stage renal disease (ESRD).
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Assessment of urine protein excretion, including measurement of a spot urine albumin-to-creatinine ratio, is critical for determining the severity of CKD and monitoring the rate of disease progression.
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The glomerular filtration rate (GFR) is the single best indicator of kidney function.
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Measurement of the GFR is most accurate when performed following the exogenous administration of iohexol, iothalamate, or radioisotopes such as technetium-99m diethylenetriamine pentaacetic acid (99mTc-DTPA).
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Equations to estimate creatinine clearance (CLcr) or GFR are commonly used in ambulatory and inpatient settings, and incorporate patient laboratory and demographic variables such as serum creatinine concentration (Scr), cystatin C, age, sex, weight, and ethnicity.
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Longitudinal assessment of GFR and albuminuria is important for monitoring the efficacy of therapeutic interventions, such as angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, which are used to slow or halt the progression of kidney disease.
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Assessments of kidney structure and function, such as radiography, computed tomography, magnetic resonance imaging, sonography, and biopsy, are predominantly used for determining the diagnosis of a given condition.
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Preclass Engaged Learning Activity
Listen to the ReachMD Podcast on “Drug Dosing Strategies for Renal Patients” (http://reachmd.com/programs/focus-on-pharmacy/drug-dosing-strategies-for-renal-patients/3426/). This podcast discusses some important differences between the eGFR that is automatically reported using the MDRD equation, and the Cockcroft–Gault equation which is most often cited in the FDA Drug Product Prescribing Information (formerly called the Package Insert or Product Label). As a companion to this activity, also become familiar with how to locate an FDA-approved drug product label using the Drugs@FDA database, available at: https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm.
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Chronic kidney disease (CKD) continues to be a worldwide health concern, with over 2 million people in the United States estimated to require hemodialysis or kidney transplantation by 2030.1 In response to this widespread problem, standardized approaches are now used for the identification of individuals with CKD and their subsequent stratification into risk categories for the development of end-stage kidney disease (ESKD or ESRD) (see Chapter 61, “Chronic Kidney Disease”).1,2 These efforts have heightened the awareness of the need for early identification of patients with CKD and the importance of monitoring the progression of kidney disease.
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Comprehensive evaluation of kidney function requires use of qualitative, quantitative, and semi-quantitative methods. Estimation of creatinine clearance (CLcr) has been considered the clinical standard for assessment of kidney function for over 50 years, and it continues to be the preferred method of characterizing kidney function for renal drug dosing purposes in pharmacokinetic studies....