and ABIM to improve CKD education for those who must engage and practice it. Timely consultation by the nephrologist in CKD promotes improved clinical outcomes and reduces the total cost of care for the patient and the public. It has been estimated that healthcare savings of $18.5 to $60.6 billion would accrue by reducing the CKD progression rate by 10–30% over the next decade. The optimal time for consultation is during CKD Stages 3–4. As eGFR falls below 45 mL/min/1.73 m2 (CKD Stage 3B), there is a significant increase in CVD risk. Crossing this eGFR threshold is equivalent to experiencing a major cardiovascular event. This risk is worsened at any CKD stage by the presence of persistent proteinuria. Estimating the GFR is important because this process not only optimizes the time of referral, but also delineates the progression rate of CKD. Urinary abnormalities, electrolyte imbalances, uncontrolled HTN, or metabolic abnormalities constitute reasons to initiate nephrological consultation. Certain conditions such as malignancy, dementia, multiple comorbidities, or an advanced directive may preclude referral to a nephrologist. Glomerular Filtration Rate (GFR) MDRD Study GFR 147 mEq/L in absence of diuretics K 5.5 mEq/L w/ dietary K restriction HCO3 28 mEq/L Resistant (“refractory” or “difficult-to-control”) Hypertension Any BP With any of the following: a) evidence of target organ damage, eg, LVH b) lack of BP control c) malignant HTN, eg, stroke, AKI/ARF, AMI, heart failure SBP/DBP 140/90 on 3 medications at full doses, including a diuretic, in non-diabetic patients without CKD SBP/DBP 130/80 on 3 medications at full doses, including a diuretic, in CKD and/or diabetic patients Proteinuria UA Dipstick 1+ (separate occasions, separated by at least 2 wk) UPC >0.2 (normal range: 30 mg albumin/g creatinine (microalbuminuria) >300 mg albumin/g creatinine (macroalbuminuria) Anemia of CKD Hb 20% and ferritin >100 ng/mL (CKD Stage 5, ferritin >200 ng/mL) 13 Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD) Alkaline Phosphatase 200 IU/L in absence of liver disease with CKD Corrected Calcium 10.2 mg/dL HCO3 28 mEq/L Phosphorus (P) >4.6 mg/dL in CKD Stages 3–4 iPTH (intact) Increasing iPTH levels with time at any CKD stage iPTH elevation above normal range, in combination with hypercalcemia, especially in early CKD stages >150 pg/mL on initial evaluation Imaging Study DEXA Evidence of vascular or cardiac calcification and/or bone loss COMMENTS • eGFR declines of >4 mL/min/1.73 m2 /yr from any cause should prompt an evaluation for acute kidney injury or rapidly progressive CKD. • Persistent asymptomatic isolated microscopic hematuria is an indication for nephrology consultation after initial imaging studies and/or urology consultation (urological consultation is recommended in cases of gross hematuria). • Persistent proteinuria is an indication for consultation by a nephrologist. REFERENCES 1. P Jungers, et al. Nephrol Dial Transplant 16: 2357, 2001 2. JL Xue, et al. J Am Soc Nephrol 12: 2753, 2001 3. KS Kinchen, et al. Ann Intern Med 137: 479, 2002 4. AG Stack. Am J Kidney Dis 41: 310, 2003 5. J Coresh, et al. J Am Soc Nephrol 14: 2934, 2003 6. EJ Kingdon, et al. Rheumatology 42: 26, 2003 7. T Kurth, et al. J Am Soc Nephrol 14: 2084, 2003 8. J Lin, et al. J Am Soc Nephrol 14: 2573, 2003 9. HS Trivedi, et al. Am J Kidney Dis. 39: 721, 2005 10. BM Curtis, et al. Nephrol Dial Transplant 20: 147, 2005 11. M Moser, et al. NEJM 355: 385, 2006 12. LE Boulware, et al. Am J Kidney Dis 48: 192, 2006 13. TD DuBose, et al. J Am Soc Nephrol 20: 681, 2009 14 15 DIABETIC KIDNEY DISEASE by Susanne B. Nicholas Diabetic kidney disease (DKD) refers to renal disease specific to diabetes that may be biopsyproven. This term may supplant “diabetic nephropathy” or diabetic CKD and is the terminology used by the National Kidney Foundation. Introduction The worldwide prevalence of diabetes mellitus (DM) is expected to be ~366 million by the year 2030, more than 2 times that from the year 2000. In the United States, 23.6 million people have DM and another 57 million have pre-diabetes or impaired glucose tolerance, and, in general, DM is linked primarily to obesity, aging, tobacco use, physical inactivity, and urbanization. DM accounts for >50% of prevalent and ~40% of US incident end-stage renal disease (ESRD) (http://www.cdc.gov/diabetes/statistics/esrd), and diabetic ESRD is significantly higher in certain ethnic and racial populations (eg, African American, Mexican American, American Indian, Inuit, Hispanic). However, the majority of people with DM are more than 64 y.o. It is well known that diabetic ESRD is associated with excess morbidity and mortality. In a prospective German study, the 5-yr survival rate was 300 mg/24 h; UACR >30 mg/g) is associated with increased progression of CKD and possibly, ESRD. The level of proteinuria >2g/24-h may be identified qualitatively by 3+ urine dipstick or followed quantitatively by the urine protein-to-creatinine ratio (UPC; normal 3.5g/24-h is considered nephrotic range proteinuria. A spot morning (0800–1200 hours) UPC has been shown to correlate well with the 24-h urine collection in patients with DKD, and therefore is also a good screening test for DKD and for monitoring patients on a stable treatment regimen. Benign proteinuria that occurs due to fever, intense