Indicator Details: Percentage of Patients Seeing a Nephrologist
Data Sources
 
Stratification and Year Choices:

  Source
  • NATIONAL VA

  Chart Format


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Clinical guidelines recommend referral to specialty nephrology care for individuals with estimated GFR < 30 ml/min/1.73 m². Specialty nephrology care prior to end-stage renal disease has been shown to improve outcomes for patients on dialysis.

This indicator only measures nephrology care within VA facilities. Some VA patients may receive nephrology care in the private sector. See Limitations in Methods section for more detail.
Chart Explanation: These charts show the percentage of patients having at least one visit with a VA nephrology clinic in the specified fiscal year within each kidney function/disease status grouping and by whether or not they have hypertension (determined by diagnosis and/or medication use). Kidney function (MDRD eGFR), dialysis, and transplant status were all determined on the basis of data from the previous fiscal year. Patients in the unmeasured category did not have a serum creatinine test in the previous fiscal year and had no indication of dialysis or transplant. Because they are monitored by a nephrologist at the dialysis clinic, dialysis patients are not shown in these graphs. Use radial buttons to see data for different years and by different CKD risk factors (age, gender, race, diabestes, and hypertension).
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, ~ 70% of the outpatient population receives a 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).

All outpatient visits from the following fiscal year are examined for nephrology clinic stops. Each year's graph shows nephrology visits that year for patients with serum creatinine testing the previous year.

This material is the result of work supported with resources and the use of facilities at the Veterans Affairs Ann Arbor Health Care System, Ann Arbor, Michigan.
FieldData
Description of MeasureNephrology care by level of kidney function and hypertension status in the previous fiscal year
Data SourceVA
Type of Data SourceAdministrative Data
Data SetVA National Data, using the MedSAS data files
Health Care System DataYes
Regional or National?National
Demographic GroupPatients using the VA health care system
NumeratorPatients in denominator with a clinic stop code indicating a nephrology visit in the specified fiscal year
DenominatorPatients aged 18 or older with at least one outpatient visit in both the specified fiscal year and the year before
Primary Data Source IndicatorNephrology clinic stop (code=313)
Primary Indicator Method of MeasurementOutpatient clinic visits
Secondary (1) VariableKidney disease status (estimated GFR, dialysis and transplant). Dialysis patients not shown.
Glomerular filtration rateEstimated using the CKD-EPI equation: eGFR=141 X min(SCR/K,1)**A X max(SCR/K,1)**-1.209 X 0.993**Age X 1.018[if female] X 1.159[if black] where SCR is serum creatinine in mg/dl, min is the minimum of SCR/K or 1, max is the maximum of SCR/K or 1, K=0.7 for female or K=0.9 for male, A is -.329 for female and -.411 for male. Missing race/ethnicity was coded as white. ** signifies "raised to the power of".
Secondary (2) VariableHypertension status (measured in same year as kidney disease status)
Secondary (2) Variable Method of MeasurementHypertension status determined by inpatient or outpatient diagnosis (ICD-9-CM code) and/or the filling of an outpatient prescription for antihypertensive medication through the VA pharmacy.
Frequency of Measurement (Primary)Multiple measurements per patient
Period Currently Available2005-2018
Limitations of Indicator

Only nephrology visits at a VA medical center are included in this indicator. Since not all VA medical centers have nephrology clinics, some VA patients may see nephrologists outside of the VA. This may underestimate the true fraction of VA patients receiving nephrology care.

Some patients shown to have Stage 5 kidney disease may be on dialysis outside of the VA system. The research data does not include care given in the private sector that is paid for by the VA (referred to as fee-basis care). Therefore, a larger portion of Stage 5 patients may have received care outside of the VA than patients with earlier stages of CKD.

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