01. Chronic Kidney Disease

Resident Editor: Michael Incze, M.D.

Faculty Editor: Leticia Rolon

BOTTOM LINE

✔ Risk of death from CV disease is usually higher than risk of ESRD

✔ ACE-I/ARB is most helpful in proteinuric CKD

✔ Proteinuria is the most significant risk factor in predicting progression to ESRD.

✔ Recommended to refer to nephrology when GFR < 30 and progressing or if other concerning features (see below)

Background

  • The prevalence of chronic kidney disease (CKD) in the U.S. adult population has been increasing from 11.5% between 1999-2006 to nearly 15% between 2011-2014 (approaching 1 in 5 patients).

Classification

  • Definition of CKD: ≥3 months of one of the following:
  1. Kidney damage (most commonly cystic kidney disease, proteinuria, hematuria)
  2. Decreased estimated glomerular filtrate rate (GFR) < 60ml/min per 1.73m2
    1. Consider calculating eGFR using Cystatin C for confirmation if eGFR in extremes of muscle mass/age.
    2. CKD-EPI is preferred way to calculate eGFR in most populations

• Staging: CGA = Cause, GFR and Albuminuria categories

Cause

GFR

(mL/min per 1.73 m2)

Albuminuria

Diabetes

Hypertension

PCKD

GN

Other

G1 (90+)

G2 (60-89)

G3a (45-59)

G3b (30-44)

G4 (15-29)

G5 (<15)

A1 (ACR <30)

A2 (ACR 30-300)

A3 (ACR >300)

 

 

 

 

 

 

 

Evaluation

  • Who to screen (serum creatinine, urinalysis with microscopy, microalbuminuria)
    • Asymptomatic adults without CKD risk factors do not need to be screened (ACP guidelines)
    • Those with risk factors
      • Most important causes of CKD development
        • DM
        • HTN
      • Other causes or risk factors:
        • Glomerulonephritis
        • Chronic interstitial nephritis or obstruction
        • Hereditary or cystic disease
        • Vasculitis
        • Neoplasm or plasma-cell dyscrasias
        • Family history of CKD
        • Recurrent UTIs
  • History
    • PMH: DM, HTN, prerenal state (CHF, cirrhosis, GI losses), HIV, HBV, HCV, SLE, urinary tract disorders
    • FHX: polycystic or medullary cystic kidney disease, Alport’s syndrome 
    • ROS: symptoms associated with underlying conditions and CKD complications (edema, hematuria, frothy urine, flank pain, rashes).
    • Review med list for nephrotoxic agents, drugs that need renal dose adjustment (antibiotics, gout medications, analgesics, NSAIDs, recurrent iodinated contrast exposure)
  • Physical – include blood pressure, signs associated with underlying conditions, CKD complications or uremia (altered mental status, volume overload, pericarditis)
  • Initial Labs/Tests
    • Everybody gets: basic metabolic panel, CBC (for anemia), lipids (for CV risk), uric acid, serum albumin, urine microalbumin and creatinine, urinalysis, renal ultrasound (for cysts/hydronephrosis), HbA1c, fasting glucose
    • If GFR <45: Ca, Phos, PTH, 25-OH Vit D to assess for mineral metabolism abnormalities
    • Consider: HIV, ANA, Hep B, Hep C, ANCA, SPEP/UPEP based on risk/history
    • Frequency of GFR and albuminuria monitoring (consider increased frequency depending on rate/degree of change):
    • Early CKD – q 1 year
    • GFR 30-45 – q 6 mo
    • GFR 20-30 – q 3 mo
    • GFR < 20 co-manage with nephrology

 

Source: 2013 KDIGO Guidelines

  • Risk factors for progression include: cause of CKD, level of GFR, level of albuminuria, age, sex, race/ethnicity, elevated BP, hyperglycemia, dyslipidemia, smoking, obesity, history of cardiovascular disease, and ongoing exposure to nephrotoxic agents.

Treatment

  • Pillars of treatment:
    • Slow CKD progression by optimizing comorbidities, primarily glucose and BP control
    • Achieve maximal suppression of proteinuria, ideally with RAAS blockade but antihypertensives in general can help lower proteinuria.
    • Treat CKD complications (metabolic acidosis, hyperphosphatemia).
    • CVD risk reduction (ASA use controversial, statin use typically accepted)

​​A. Treatments to slow progression

  • Blood pressure goals should be individualized based on age, tolerance to treatments and co-morbidities.  In general, treat to a goal of <140/90 in patients with urinary albumin excretion >30mL/24h.  Treat to a goal SBP <130/80 if urinary albumin excretion is >30mL/24h.
  • ACE-I or ARB for diabetics with albumin excretion of 30-300mg/24 hr, for any patient with albumin excretion > 300/24hr and for all patients with CKD and hypertension
    • Main benefit in CKD without proteinuria is related to BP control
    • No benefit to combination therapy with ACE-I & ARB and there is potential harm
    • Must monitor for hyperkalemia
  • Smoking cessation
  • Sodium bicarb to maintain serum bicarb >22
  • Target glucose control of ~HbAlc 7%
    • Suggested target < 8% if at risk for hypoglycemia, older than 70 years, or if other comorbidities
  • Statins: prevent CVD but do not affect CKD progression

B. Anemia

  • An early manifestation of kidney disease which starts when GFR <60 mL/min. 
  • Check iron panels and rule out GI bleeding.  Do NOT check erythropoietin levels, but consider hematology referral if anemia out of proportion to kidney disease. 
  • SPEP/UPEP/immunofixation (IFE) indicated in patients >50 years, especially with proteinuria, hypercalcemia, or disproportionate anemia. 
  • Refer to nephrology for further management (such as with erythrocyte stimulating agents)

C. Renal Osteodystrophy/Secondary Hyperparathyroidism

  • Starting with CKD stage 3, consider checking calcium, phosphorus, and PTH
  • Vit D supplementation if 25-hydroxy vit D < 30 ng/mL. Supplement with ergocalciferol 50,000 units PO weekly x 12 weeks, then 50,000 units PO monthly. Daily oral doses may also be used based on PTH response.
  • Goal is to keep phosphorus within normal range. Use phosphorus restriction (800-1000mg/day) and/or phosphate binders.
  • Keep in mind that patients with secondary or tertiary hyperparathyroidism typically have much higher PTH levels than those with primary hyperparathyroidism.
  • Use more potent forms of Vit D in consultation with nephrology

D. Nutrition

  • Salt restriction (<2g/day) especially with GFR < 30
  • Fluid restriction if edematous
  • Regular monitoring of nutritional status

E. Other issues

  • In stage 4-5 CKD, avoid venipuncture, IV placement, PICC lines, and subclavian catheters in arm most suitable for future vascular access (usually non-dominant arm)
  • Pneumococcal vaccine (both PPS-23 and PCV-13) should be administered once, at least one year apart, and yearly flu vaccine. Hepatitis B vaccination if progressing to dialysis and/or transplantation.
  • Patients with CKD should be considered at incrased risk for developing acute kidney injury
  • Recommendations state that level of care offered for ischemic heart diseased should not be prejudiced by presence of CKD

 

When to Refer to Nephrology

  • eGFR <30 and progressing – for dialysis planning and transplant consideration
  • Hematuria that is not readily explained
  • Significant proteinuria
  • Persistent abnormalities of serum potassium
  • Hereditary kidney disease
  • Late nephrology referral is associated with increased mortality after dialysis initiation. Referral is “late” when within one to six months of the requirement for renal replacement therapy

When to Refer to Urology

  • Recurrent/extensive nephrolithiasis
  • Obstructive nephropathy

References

Carville, S., et al. “Early Identification and Management of Chronic Kidney Disease in Adults: Summary of Updated NICE Guidance.” Bmj, vol. 349, no. jul24 2, 2014, doi:10.1136/bmj.g4507.

Stevens, Paul E. “Evaluation and Management of Chronic Kidney Disease: Synopsis of the Kidney Disease: Improving Global Outcomes 2012 Clinical Practice Guideline.” Annals of Internal Medicine, vol. 158, no. 11, Apr. 2013, p. 825., doi:10.7326/0003-4819-158-11-201306040-00007.

Aboud H and Henrich W. Stage IV Chronic Kidney Disease. New England Journal of Medicine. 2010; 362(1);56-65

Coresh J, Selvin E, Stevens LA, et al. Prevalence of chronic kidney disease in the United States. JAMA. 2007; 298(17):2038–2047.

De Brito-Ashurst I, Varagunam M, Raftery MJ, Yaqoob MM. Bicarbonate Supplementation Slows Progression of CKD and Improves Nutritional Status. Journal of the American Society of Nephrology. 2009; 20(9):2075–2084.

Drawz P, Rahman M, Laine C, Goldmann DR, Sox HC. Chronic Kidney Disease. Annals of Internal Medicine. 2009; 150(3):ITC2–1.

Inker A, Astor B, Fox C, et al. KDOQI US Commentary on the 2010 KDIGO Clinical Practice Guideline for the Evaluation and Management of CKD. American Journal of Kidney Disease. 2014; 63(5):713-735.

Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney inter., Suppl. 2013; 3: 1-150.

Levey A, Coresh J, Balk E, et al. National Kidney Foundation Practice Guidelines for Chronic Kidney Disease: Evaluation, Classification, and Stratification. Annals of Internal Medicine. 2003; 139:137-147.