Most veterans did not progress to another CKD stage in one year. CKD stages 1 and 2 had the most patients decreasing a stage in severity over one year. This may be due to serum creatinine measurements near the stage boundaries, such as someone who had an estimated glomerular rate (eGFR)=61 in 2017 and an eGFR=58 in 2018.
Chart Explanation: The chart compares the percentage of veterans in each stage of chronic kidney disease (CKD) in 2018 to their CKD stage in 2017. The bars represent each stage of CKD in 2017. For example, of the patients in 2018 who were in CKD stage 3, none had been in CKD stage 1 the year before (2017), 8% had been in CKD stage 2, 71% had been in CKD Stage 3 the prior year, 18% had been in CKD Stage 4, and 3% had been in CKD stage 5 (not end-stage renal disease, or ESRD).
The VA data presented are from a national sample of health care visits to the VA Health System by eligible US veterans. During any given year, approximately 70% of the outpatient population receives a serum creatinine test. Although the demographics of VA Health System users are distinct from the general US population, the VA data provide 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 CKD prevalence, outpatient serum creatinine laboratory results (averaged if a patient had more than one test during the fiscal year) were used to calculate an eGFR for each patient using the CKD-EPI equation, excluding dialysis and transplant patients. The eGFR (or measure of kidney function) was classified into five CKD categories—eGFR ≥90, eGFR 60-89, eGFR 30-59 (stage 3), eGFR 15–29 (stage 4), and eGFR<15 ml/min/1.73 m² (stage 5 without dialysis)—and into “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.
Because of the infrequency of testing, albuminuria (protein in the urine) 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), and outpatient diagnostic codes (ICD-9-CM: 585.6, V56, V45.1 and E87.91 and ICD-10-CM: N18.6, Y84.1, Z49.31, Z49.01, Z49.02, Z49.31, Z49.32, and Z49.33) to indicate dialysis. Kidney transplant patients were identified by inpatient and outpatient ICD-9-CM diagnostic codes V420 and 996.81, ICD-10 CM diagnostic codes T86.X, Z48.22, and Z9.40, and inpatient procedure and surgery code 55.69. Dialysis and transplant patients are not included in stage 5.
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.
| Field | Data |
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| Description of Measure | Prevalence of reduced eGFR and CKD by stage. |
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| Data Source | VA |
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| Type of Data Source | Administrative data |
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| Data Set | VA national data, using the MedSAS data files |
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| Health Care System Data | Yes |
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| Regional or National | National |
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| Demographic Group | Patients in VA system |
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| Numerator | Patients in the denominator with available serum creatinine results in the specified eGFR category (≥90 and 60-89 ml/min/1.73 m²) or CKD stage (3–5). |
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| Denominator | Patients aged 20 or older who have had at least one outpatient visit or at least one outpatient serum creatinine measurement. |
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| Definition of CKD | eGFR > 90 ml/min/1.73 m² (CKD stage 1), eGFR 60-89 ml/min/1.73 m² (CKD stage 2), eGFR 30-59 ml/min/1.73 m² (CKD stage 3), eGFR 15-29 ml/min/1.73 m² (CKD stage 4), eGFR <15 ml/min/1.73 m² (CKD stage 5), on dialysis (CKD stage 5D), and transplant (CKD stage 5T). ESRD is Stage 5D and Stage 5T. |
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| Glomeruler Filtration Rate | Estimated 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 and K=0.9 for male,
A is -0.329 for female and -0.411 for male. Missing race/ethnicity was coded as white. ** signifies "raised to the power of". |
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| Primary Data Source Indicator | Serum creatinine lab result value |
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| Primary Indicator Method of Measurement | Laboratory: A valid serum creatinine value was defined as 0.3-15.0 mg/dl. Any values outside this range were set to “missing.” No more than 1% of serum creatinine values in each cohort were outside this range. |
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| Frequency of Measurement (Primary) | Multiple measurements per patient |
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| Period Currently Available | 2018 |
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| Limitations of Indicator | Use of methods to standardize creatinine varies by facility. True occurrence of CKD stages 1 and 2 cannot be calculated due to the low rate of urine albumin testing. |
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References and Sources:
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Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Modification of Diet in Renal Disease Study Group. Ann Intern Med. 1999;130(6):461-70.
http://www.ncbi.nlm.nih.gov/pubmed/10075613