Indications for Referrals:

In 2002, the National Kidney Foundation’s Kidney Disease Outcomes and Quality Initiative (K/DOQI) developed a staging process for chronic kidney disease (CKD) based on glomerular filtration rate (GFR). GFR may be estimated by creatinine clearance using several readily available calculations MDRD formula link Many major labs are now providing an estimated GFR automatically when a serum creatinine is ordered. Both the International Classification of Diseases (ICD) and the Centers for Medicare & Medicaid Services (CMS)  have adopted CKD staging for billing and coding purposes.

Staging and Prevalence of CKD in the United States (Age ≥ 20 years)
Stage

Table adopted from K/DOQI Executive Summary 2002. Data for Stages 1-4 from NHANES III (1988-1994) population of 177 million adults age ≥ 20 years. Data for Stage 5 from USRDS 1998. For Stages 1 and 2, kidney damage is estimated by elevated spot albumin-to-creatinine ratio of > 17mg/g in men, > 25mg/g in women on two measurements.
*Stage 5 is split into patients not yet on renal replacement therapy (RRT) (585.5) versus those on RRT (585.6), e.g. dialysis or transplant. More recent data place the Stage 5 population on RRT well above 300,000, with more than 80,000 living with transplants.

Referral to a nephrologist is recommended at CKD Stage 1 or 2 if there is unexplained proteinuria or hematuria or difficult to control hypertension, edema, renal calculi, or polycystic kidney disease. We recommend referral at least by Stage 3 for all diabetics and hypertensives for medication review and comanagement in order to slow the rate of progression of CKD. Patients often have sequellae of CKD like secondary hyperparathyroidism and anemia of CKD by this stage that may benefit from evaluation and management. Certain medications such as gabapentin and digoxin require dose adjustment by Stage 3, and certain medications such as metformin are contraindicated. Patients often develop edema, hyperkalemia, and metabolic acidosis by Stage 4 that may benefit from nephrology comanagement. Patients may be making preparations for renal replacement therapy (e.g. arteriovenous fistula for hemodialysis, peritoneal dialysis catheter referral, transplant referral) or may benefit from education about hospice from a renal perspective. Urgent referral is recommended at Stage 5 for renal replacement therapy or hospice education as well as the indications noted above.