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Approach to Chronic Kidney Disease

Terra Swanson

Definition of CKD

  • Decreased kidney function or one or more markers of kidney damage for 3 or more months

  • History of kidney transplant

  • GFR \< 60; Staging helps risk-stratify pts likely to progress or develop complications of CKD

    • CKD IIIa: eGFR 45-60
    • CKD IIIb: eGFR 30-44
    • CKD IV: eGFR 15-30
    • CKD V: eGFR \< 15
  • Markers of kidney damage

    • Albumin/Cr ratio

      • Mild: 0-30 mg/g

      • Moderate: 30-300 mg/g

      • Severe: >300 mg/g

  • Urine sediment: RBC casts, WBC casts, oval fat bodies or fatty casts, granular casts

  • Electrolyte derangements

  • Abnormalities on histology

  • Structural abnormalities: (cysts, hydronephrosis, scarring, masses, renal artery stenosis)

When to refer to nephrology clinic

  • eGFR \< 45

  • Persistent urine albumin/creatinine ratio > 300 mg/g

  • Urine protein/creatinine ratio greater than 500 mg/g

  • Rapid loss of kidney function (> 30% decline over 4 months)

  • Hematuria not 2/2 urologic condition or if there are RBC casts on UA

  • Inability to identify presumed cause of renal dysfunction

  • Difficult to manage complications (hyperkalemia, anemia, bone-mineral disease, HTN)

  • Confirmed or presumed hereditary kidney disease (PCKD suspected)

Complications of CKD

  • Imbalance of water homeostasis
    • As renal mass declines the ability to both concentrate and dilute the urine is impaired
    • This manifests as hyponatremia (no end-organ to respond to ADH) and edema
    • Treat this with water restriction, diuretics or, eventually, ultrafiltration

Metabolic acidosis

  • Correcting serum bicarbonate to a goal of 23-30 meq/L slows decline in renal function and protects against bone-mineral complications of chronic metabolic acidosis

  • Can calculate bicarbonate deficit to estimate dose of bicarbonate

  • If bicarb \< 22, consider:

    • Sodium bicarb 650 mg TID (8mEq bicarb per 650mg tablet) up to 5850mg/day (70 mEq or 3 tabs TID)
    • Sodium citrate (Bicitra): 1mL = 1 mEq * Careful in cirrhosis since citrate cannot be metabolized
    • Baking soda (sodium bicarbonate): 1 teaspoon = 59 mEq HCO3 (careful of Na load)


  • Goal BP \< 120/80 (Class 2B recommendation) based on SPRINT trial, ACC/AHA 2017, and KDIGO 2021 guidelines

  • All comers: Diet (e.g. DASH) and lifestyle modifications

  • CKD without albuminuria or DM:

    • Start pharmacotherapy based on ASCVD risk as well as risk for other target organ damage
  • CKD with moderate to severe albuminuria w/ or w/out DM

    • ACEi or ARB titrated to maximally tolerated dose (Class 1B recommendation)
    • Thiazide-like diuretics (see CLICK trial for chlorthalidone in advanced CKD)
    • Loop diuretics can assist with volume driven HTN in patients with CKD 4-5
  • HTN in kidney transplant

    • CCBs or ARBs are first line (Class 1C recommendation)
  • Consider stopping ACE-i/ARB if:

    • GFR declines >30% over 4 months. Consider evaluation for renal artery stenosis
    • K > 5.5 despite low K diet, optimizing dose of diuretics, or adding K-binders

Anemia in CKD

  • Multifactorial: decreased EPO production, impaired iron absorption, uremic toxins suppressing bone marrow, loss of blood in dialysis circuit, and from GI AVMs

  • Indications for iron supplementation in non-dialysis patients:

    • ALL patients with TSAT \<20% and ferritin \<100 ng/mL
    • Patients with Hb \<13 and TSAT \<30% and ferritin \<500 ng/mL
    • Can start with PO supplementation (see Anemia section). Reassess iron levels in 1-3 mos; if not appropriately ↑, consider IV iron repletion
  • Dialysis patients:

    • IV Iron preferred method of repletion for HD patients with
      • TSAT \< 20% and ferritin \< 200
      • TSAT \<30% and ferritin \<500 AND with Hb \< 10 OR are on EPO
  • Dosing: usually administered at HD sessions - 125 mg ferric gluconate at consecutive HD sessions x 8 doses - 100 mg iron sucrose at consecutive HD sessions x 10 doses - Ferumoxytol 510mg at the end of two HD sessions 1-4 weeks apart

  • Indications for EPO

    • Pts w/ Hb \<10 who are not iron deficient (ferritin >500) or who’s anemia persists despite adequate iron repletion

Hyperkalemia (Goal K \< 5.5)

  • Patients with diabetic nephropathy (T4 RTA) and CKD 5-ESRD are at the highest risk

  • Strategies to mitigate hyperK

    • Low K diet (\< 40-70 mEq/day or 1500-2700 mg/day)

    • Loop diuretics

    • GI cation exchangers

      • Patiromer (Veltassa): binds K in colon in exchange for calcium

      • Sodium zirconium cyclosilicate (Lokelma): binds K throughout intestine in exchange for sodium and H+

      • Do not use Kayexelate as chronic therapy

  • Treat metabolic acidosis

Mineral bone disease in ESRD

  • Avoid calcium supplementation in mild or asymptomatic hypocalcemia

  • Replace vitamin D to >20 (weak evidence)

  • Phos goal \< 5.5

    • Sevelamer: use lowest dose effective to achieve Phos \< 5.5

      • Phos 5.5-7.5: initial dose 800 TID with meals

      • Phos 7.5-9.0: initial dose 1200-1600 TID with meals

      • Phos > 9: initial dose 1600 TID

      • Can titrate dosing by 400 to 800 mg per meal at 2-week intervals

    • Restrict dietary phos to 900 mg/day

  • PTH goal in CKD3: 2x ULN

  • PTH Goal in ESRD: 2-10x ULN

Diabetes in CKD

  • Individualize A1C goals. Both the ADA and VA-DOD have guidelines for selecting A1C targets

  • Treatment:

    • Metformin remains first-line but should be dose-reduced based on eGFR

      • eGFR > 45: Maximum daily dose of 2000mg/day (1000mg bid)

      • eGFR \< 45: Reduce max daily dose to 1000mg/day (500mg bid)

      • eGFR \< 30: Discontinue if high risk for volume mediated AKI/chronically ill

    • SGLT-2 inhibitors for patients with eGFR > 30 reduces progression to ESRD and death from renal or cardiovascular cause (Evidence: DAPA-CKD, CREEDENCE)

    • Finerenone (non-steroidal MRA)- would ask nephrology for help if considering this option since relatively new and increased risk for hyperkalemia. (Evidence: FIDELIO)

Dialysis initiation

  • Early (CKD3a or 3b) referral to nephrology has better outcomes

  • Uremic symptoms: fatigue, sleep disturbance, N/V, decreased appetite, dysgeusia, itching, hiccupping

  • Refractory hyper K

  • Refractory hypertension

  • Plot your patient’s eGFR using the graph function in EPIC or CPRS to determine trajectory (normal age-related decline after age 60 is ~ 1ml/min/m2)