2. Objectives Understand the definition of CKD Describe risk factors for CKD Become familiar with estimated GFR (eGFR) as a measure of kidney function
3. Impact of Kidney Disease in NC 1 million living with CKD in NC 11,000 people currently on dialysis in NC NC ranks 10th highest in the country in prevalence of end stage renal failure (ESRD)
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6. Background NKF = National Kidney Foundation 1995 developed clinical practice guidelines for dialysis patients DOQI = Dialysis Outcomes Quality Initiative 1st published in 1997 Realization: to improve dialysis outcomes, it is necessary to improve the health status of those who are reaching ESRD
7. Background Fall 1999, NKF approved proposal to move the clinical practice guideline initiative into a new phase Scope would include the entire spectrum of kidney disease Guidelines renamed KDOQI (=Kidney Disease Outcomes Quality Initiative) Centerpiece of KDOQI is 2002 “Clinical Practice Guidelines on the Evaluation, Classification, and Stratification of CKD”
8. Ann Intern Med 2003; 139:137-47 http://www.annals.org/cgi/reprint/139/2/137.pdf Am Fam Physician 2004; 70:869-76 http://www.aafp.org/afp/20040901/869.pdf
9. NKF K/DOQI Definition of Chronic Kidney Disease Structural or functional abnormalities of the kidneys for >3 months, as manifested by either: 1. Kidney damage, with or without decreased GFR, as defined by pathologic abnormalities markers of kidney damage urinary abnormalities (proteinuria) blood abnormalities imaging abnormalities kidney transplantation 2. GFR <60 ml/min/1.73 m2, with or without kidney damage
10. Is the Kidney Failure Acute or Chronic? Acute Chronic Hx normal kidney function Normal sized kidneys Normal echotexture Normal to slightly decr. Hgb/Hct intact PTH normal Acute process on kidney biopsy Often active urine sediment Hx altered kidney function Small sized kidneys Increased echogenicity Anemia intact PTH elevated Chronic scarring on kidney biopsy Chronic findings on U/A
11. Assessing CKD risk All individuals should be assessed to determine if they are at increased risk of developing CKD Individuals at increased risk of developing CKD should undergo testing for markers of kidney damage and to estimate the level of GFR Those at risk, but without CKD, should be advised about risk factor reduction and undergo repeat periodic evaluation Am J of Kidney Diseases 39(2)Suppl 1, 2002:ppS7-S10
12. Types and Examples of Risk Factors for CKD Am J of Kidney Diseases 39(2)Suppl 1, 2002:ppS7-S10
14. Relationship between the type of kidney disease and risk factors Am J of Kidney Diseases 39(2)Suppl 1, 2002:ppS7-S10
15. Prevalence of CKD by risk factor Am J of Kidney Diseases 39(2)Suppl 1, 2002:ppS7-S10
16. Who is at risk for CKD: the short list Diabetes Mellitus Hypertension Family history of CKD U.S. ethnicity status African American American Indian Hispanic Asian Pacific Islander
17. The Risk of Kidney Failure is Not Uniform Relative risks compared to Whites: African Americans3.9 X Native Americans2.9 X Asians1.6 X From NKDEP; USRDS, 2003
18. What is GFR? Glomerular filtration rate For the patients, “% kidney function” Excellent measure of the filtering capacity of the kidneys Total GFR = # of nephrons x GFR of a single nephron Varies according to age, gender, body size
19. How to measure or estimate GFR Ideal measure of kidney function Iothalamate, inulin, iohexol Serum level of creatinine (endogenous filtration marker) traditionally used to estimate GFR Problems include: tubular secretion, generation, 50% loss of function before Cr becomes abnormal
20. How to estimate GFR Creatinine clearance – approximates GFR Problems include those with serum creatinine, collection difficulties/inaccurate, overestimation of GFR due to tubular secretion of creatinine Estimation of creatinine clearance – Cockcroft-Gault equation MDRD study equation estimates GFR standardized for body surface area (BSA)
21. How to estimate GFR: use the abbreviated MDRD study equation 4 variable MDRD equation Serum creatinine Age Gender Ethnicity Easy to implement Rigorously validated Recommended by NKDEP, NKF, NIDDK, ASN http://www.kidney.org/professionals/kdoqi/gfr_calculator.cfm
22. Take home messages eGFR > 60cc/min with kidney damage is CKD eGFR < 60cc/min is CKD Must be abnormal x 3 mos duration Remember the short list of risk factors: the big 4 eGFR is a 4 variable equation based on age, gender, ethnicity, Creatinine. Labcorps makes it easy for you because they tell you if the eGFR is abnormal (with one exception…)
23. NKDEP National Kidney Disease Education Program www.nkdep.org NKF National Kidney Foundation www.kidney.org
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25. This must be a collaborative effort with primary physicians: 7.6 million people with GFR 30-60 mL/min/1.73 m2 About 5,000 full-time nephrologists Nearly 1,500 new patients per nephrologist Therefore, 7 new patients per day per nephrologist. Obviously not possible. http://www.nkdep.nih.gov/index.htm
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27. Prevalence* GFR (ml/min/1.73 m2 Description Stage % N (1000s) 3.3 5,900 90 Kidney Damage with Normal or GFR 1 3.0 5,300 60-89 Kidney Damage with Mild GFR 2 4.3 7,600 30-59 Moderate GFR 3 0.2 400 15-29 Severe GFR 4 0.1 300 < 15 or Dialysis Kidney Failure 5 Prevalence of CKD and Estimated Number of Adults with CKD in the US (NHANES 88-94) *Stages 1-4 from NHANES III (1988-1994). Population of 177 million with age 20. Stage 5 from USRDS (1998), includes approximately 230,000 patients treated by dialysis, and assuming 70,000 additional patients not on dialysis. GFR estimated from serum creatinine using MDRD Study equation based on age, gender, race and calibration for serum creatinine. For Stage 1 and 2, kidney damage estimated by spot albumin-to-creatinine ratio 17 mg/g in men or 25 mg/g in women in two measurements.
