Note from the Instructor: A CKD primer

July 13, 2021
CDI Blog - Volume 14, Issue 26

By Laurie L. Prescott, RN, MSN, CCDS, CCDS-O, CDIP, CRC

The kidneys filter waste and excess fluid from the blood. As kidneys fail, these wastes build up.

The symptoms of chronic kidney disease (CKD) generally develop slowly and aren't specific to the disease. Often, there are no noticeable symptoms, and the condition is noted incidentally from a diagnostic testing, or the symptoms first appear once the disease course has reached significant impairment.

Treatment for CKD focuses on slowing the progression of the kidney damage, usually by controlling the underlying cause. CKD can progress to end-stage kidney failure, which is fatal without artificial filtering (dialysis) or a kidney transplant.

Supportive symptoms for the diagnosis of CKD may include:

  • Nausea
  • Vomiting
  • Loss of appetite
  • Fatigue           
  • Disruption of sleep
  • Disruption in urination patterns
  • Altered Mental function
  • Muscle cramping and twitching movements
  • Peripheral edema
  • Dry skin and itching
  • Chest pain
  • Heart failure
  • Hypertension

There are a number of conditions that contribute to CKD to include the common contributing factors of diabetes mellitus and hypertension. Other conditions such as s glomerulonephritis, interstitial nephritis, polycystic kidney disease, prolonged urinary tract obstruction, vesicoureteral reflux, and reoccurring pyelonephritis may also contribute to chronic renal disease.

Patients who have undergone kidney transplant may still demonstrate CKD because the transplant may not fully restore renal function. The presence of CKD alone does not support a transplant complication. If the documentation is unclear as to whether the patient has a complication of transplant, the provider should be queried.

Common comorbidities besides those listed above include cardiovascular disease, tobacco dependence, morbid obesity, and congenital kidney disease. Other risk factors include advanced age, a family history of kidney disease, and race (African American, Asian American, and indigenous populations).

The diagnosis of CKD describes abnormal renal function. The National Kidney Foundation Kidney Disease Outcome Quality Initiative (NKF KDOQI) defines CKD as damage for greater than three months, defined by structural or functional abnormalities of the kidney, with or without a decreased glomerular filtration rate (GFR), that can lead to a decreased GFR. The diagnosis can be made based upon pathological abnormalities present in imaging or diagnostic markers such as abnormalities in the blood or urine composition, that result in “implications of health.”

The NKF KDOQI diagnostic criteria includes at least three months trending data demonstrating:

  • Decreased GFR < 60 mL/min OR
  • Objective findings:
    • Albuminuria: albumin excretion rate (AER) > 30 mg/24 hours or albumin to creatinine ratio (ACR) > 30 mg/g
    • Abnormal urine sediment
    • Electrolyte and other abnormalities due to renal tubular disorders
    • Histological abnormalities noted in pathology
    • Structural abnormalities found in imaging
    • History of renal transplant

CKD is classified into five stages of severity and end-stage renal disease (ESRD), which is stage 5 CKD in a patient described as dialysis dependent. The GFR is used to classify the severity, based upon trending lab data.

Stage

Description

eGFR

At

increased risk

Risk factors for kidney disease

(diabetes, hypertension, family history, age, ethnicity)

>90

1

Kidney damage with normal kidney function

>90

2 (mild)

Kidney damage with mild loss of kidney function

89-60

3a (moderate)

Mild to moderate loss of kidney function

59-44

3b (moderate)

Moderate to severe loss of kidney function

43-30

4 (severe)

Severe loss of kidney function

29-15

5

Kidney Failure

<15

*If the provider documents chronic dialysis is required end stage renal disease should be reported.

GFR describes the flow rate of filtered fluid through the kidney. The GFR will vary based on an individual’s age, sex, and race. Most organizations will calculate the estimated (eGFR) combined with creatinine reporting.

The creatinine level must be stable to adequately diagnose CKD. If the creatinine level fluctuates during an admission, the eGFR based on the lowest creatinine level should be used to compute the eGFR. Access to the patient’s historical medical record and historical trending data (prior three months) provides a more reliable eGFR on which to stage the level of severity.

 

CKD stages 4 and 5 provide a CC as a secondary diagnosis. ESRD provides an MCC.

CKD stages 3, 4, 5, and ESRD contribute to CMS-Hierarchical Condition Category risk adjustment and impact hospital ranking within the U.S. News & World Report.

Reference:

  • Inker, L.A., Astor, B. C., Fox, C. H., Isakova, T., Lash, J. P., Peralta, C. A., Feldman, H. I. (2014). KDOQIUS commentary on the 2012 KDIGO clinical practice guideline for the evaluation and management of CKD. American Journal of Kidney Diseases, 63(5), 712-735. https://doi.org/10.1053/j.ajkd.2014.01.416

Editor’s note: Prescott is the CDI education director at HCPro in Middleton, Massachusetts. Contact her at lprescott@hcpro.com. For information regarding CDI Boot Camps, click here.