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Indicator Details: Serum Creatinine (scr) Test Following Scr Defined AKI Within 6 Months of Discharge
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Chart Explanation: 
The Veteran’s Affairs (VA) data presented are from a national sample of health care visits to the VA Health System by eligible U. S. veterans. During any given year, roughly 70% of the outpatient population receives at least one serum creatinine test. While the demographics of VA Health System users are distinct from the general U.S. population, the VA data allow a snapshot of clinical practices across the nation.

National VA data were examined for veterans with at least one outpatient visit during the federal fiscal year. To estimate prevalence of CKD, outpatient serum creatinine laboratory results (averaged if a patient had more than one test during the fiscal year) were used to calculate an estimated glomerular filtration rate (eGFR) for each patient using the CKD-EPI equation, excluding dialysis and transplant patients. Estimated GFR (kidney function) was classified into five CKD categories (eGFR =90, eGFR 60-89, stage 3=eGFR 30-59, stage 4=eGFR 15 to 29, and stage 5 without dialysis=eGFR<15 ml/min/1.73 m² and “eGFR Unmeasured” for those patients without serum creatinine testing. Inpatient serum creatinine data were not used as they would be affected by the presence of acute illnesses. Due to the infrequency of testing, albuminuria was not included in the definition of CKD. Dialysis patients were defined by clinic stop-codes (602-611), outpatient procedure codes for dialysis (CPT4: 90921 and 90925), outpatient diagnosis codes (ICD-9-CM: 585.6, V56, V45.1 and E87.91) and inpatient and outpatient diagnosis codes (ICD-9-CM: 5856) to indicate dialysis. Kidney transplant patients were identified by inpatient and outpatient ICD-9-CM diagnosis code V420 and inpatient procedure and surgery codes (55.69).

To examine acute kidney injury (AKI) in the hospital setting within the VA, we determined an index hospitalization for each fiscal year. This was the patient's first hospitalization of the year that had a length of stay of 2 days or more with 2 or more inpatient serum creatinine test results. A baseline serum creatinine measurement was determined from outpatient serum creatinine test results at least 7 days prior to the index hospitalization. Patients with evidence of pre-admission end-stage renal disease or a baseline MDRD estimated GFR less than 15 were excluded. An episode of AKI during the index hospitalization was defined by an increase in serum creatinine from baseline of 0.3mg/dL that did not decrease within 48 hours.

All outpatient lab results between discharge and 6 months post discharge for patients alive 6 months after discharge were examined to see if a serum creatinine test was performed.

This material is the result of work supported with resources and the use of facilities at the Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan.
Description of MeasurePercentage of patients with in-hospital acute kidney injury as defined by Acute Kidney Injury Network (AKIN) criteria that had a serum creatinine test performed within 6 months following discharge
Data SourceVA
Type of Data SourceAdministrative Data
Data Set VA National 5% Sample (FY05-FY09) and 100% (FY10-present)
Health Care System DataYes
Regional or National?National
Demographic GroupPatients using the VA health care system
NumeratorPatients in the denominator with a record of a serum creatinine text within 6 months of discharge from the hospital stay where they experienced acute kidney injury
DenominatorPatients with an episode of AKI within their index hospitalization for the specified fiscal year who survived at least 6 months after discharge
Index HospitalizationThe patient's first hospital stay of 2 days or longer with at least 2 serum creatinine measurements during the specified fiscal year
Baseline kidney functionBaseline serum creatinine was designated as the lowest serum creatinine measurement less than 90 days before admission, but no closer than 7 days before admission. If there was no serum creatinine test result in the that time frame, baseline serum creatinine was designated as the closest test result to admission from tests performed 90 to 365 days before admission. If there still was no outpatient serum creatinine result for the patient, baseline serum creatinine was taken from outpatient results within 7 days of admission or the first inpatient serum creatinine.
Acute Kidney Injury Network criteria for AKI
  • Stage 1: Increase in serum creatinine of more than or equal to 0.3mg/dl (26.4 umol/l) or increase to more than or equal to 150% to 200% (1.5- to 2-fold) from baseline or urine output less than 0.5 mg/kg per hour for more than 6 hours.

  • Stage 2: Increase in serum creatinine to more than 200%-300% (2- to 3-fold) from baseline or urine output less than 0.5 mg/kg per hour for more than 12 hours.

  • Stage 3: Increase in serum creatinine to more than 300% (3-fold) from baseline (or serum creatinine of more than or equal to 4.0mg/dl [354 umol/l] with an acute increase of at least 0.5 mg/dl [44 umol/l]) or urine output less than 0.3 mg/kg per hour for 24 hours or anuria for 12 hours.

 Note that only the serum creatinine criteria were used for this measure.

Primary Data Source IndicatorSerum creatinine lab result within 180 days of discharge
References and Sources:
  • Mehta RL, Kellum JA, Shah SV, et al. Acute Kidney Injury Network: report of an initiative to improve outcomes in acute kidney injury. Crit Care. 2007;11(2):R31.
  • Kidney Disease: Improving Global Outcomes (KDIGO) Acute Kidney Injury Work Group. KDIGO Clinical Practice Guideline for Acute Kidney Injury. Kidney Int. Suppl. 2012;2(1):1-138..

Suggested Citation:
Centers for Disease Control and Prevention. Chronic Kidney Disease Surveillance System—United States.
website. http://www.cdc.gov/ckd