Alternatives for Computing or Reporting eGFR from Serum Markers.*
| Method | Input Variables | KDIGO Recommended |
External Validation |
Coefficient for Black Race (value) |
Development Data Representation |
Overall Accuracy vs. eGFRcr |
Median Bias | Availability (Reason) |
|---|---|---|---|---|---|---|---|---|
|
no. of persons (% Black) |
ml/min/11.73 m2 | |||||||
| eGFRcr | Creatinine, age, sex, race | Yes | Yes | Yes (1.159) | 8254 (31.5) | (Baseline) | Black: 0.0; White/ Other: −0.5 |
Yes (implemented in nearly all hospitals) |
| eGFRcr-cys | Creatinine, cystatin, age, sex, race |
Yes | Yes | Yes (1.080) | 5352 (40.0) | Higher | Black: −0.3; White/ Other: 0.0 |
Yes; limited (cystatin C assay currently not widely accessible) |
| eGFRcys | Cystatin, age, sex | Yes | Yes | No | 5352 (40.0) | Equal | Black: 0.0; White/ Other: −0.5 |
Yes; limited (cystatin C assay currently not widely accessible) |
| eGFRcr with “Black” and “White/Other” relabeled as the high and low ends of an eGFR range | Creatinine, age, sex | No | No | No | Not fitted from Data (NA) |
Unknown, most likely lower | Unknown | Yes (implemented in some hospitals) |
| eGFRcr with “Black” relabeled as “high muscle mass” and “White/Other” as “low muscle mass” | Creatinine, age, sex | No | No | No | Not fitted from Data (NA) |
Unknown, most likely lower |
Unknown | Yes (implemented in some hospitals) |
| eGFRcr with race coefficient removed | Creatinine, age, sex | No | No | No | 8254 (31.5) | Lower | Black: −6.1; White/ Other: −0.5 |
Yes (implemented in some hospitals) |
| eGFRcr refitted without race variable | Creatinine, age, sex | No | No | No | 8254 (31.5) | Lower | Black: −4.0; White/ Other: 1.4 |
No (equation parameters not available) |
| eGFRcr refitted with height and weight replacing race | Creatinine, age, sex, height, weight |
No | No | No | 8254 (31.5) | Lower | Black: −3.7; White/ Other: 1.3 |
No (equation parameters not available) |
| Blended eGFRcr (weighted combination of race-specific outputs) | Creatinine, age, sex | No | No | No | 8254 (31.5) | Unknown, most likely lower |
Unknown likely negative for Black and positive for White |
Yes (multiple options for weighting) |
| eGFRmet | Acetylthreonine, phenyl-acetylglutamine, tryp-tophan, pseudouridine | No | No | No | 2424 (51.8) | Higher | Black: −1.4; White/ Other: 1.3 |
No (assays not available) |
| eGFR-LMWPs | Creatinine, cystatin C, B2M, BTP, age, sex |
No | Yes | No | 5017 (38.5) | Higher | Black: −1.1; White/Other: 0.4 |
No (assays not widely available) |
Accuracy is defined relative to the baseline of eGFRcr on the basis of a statistically significant difference (P<0.05) in either the root mean squared error of eGFR relative to mGFR (log-log scale) or 1 minus P30% (defined as <30% difference from mGFR). All data sets had a mean mGFR of 68 ml/min/1.73 m2, except eGFRmet (55 ml per minute per 1.73 m2 of body-surface area) and eGFR-LMWP (58 ml per minute per 1.73 m2). The median bias is the median difference between eGFR and mGFR in the development data. Some previous CKD-EPI studies reported bias differently, as mGFR minus eGFR. The mean bias is expected to be zero in development data sets overall and in race subgroups if there is a race coefficient. B2M denotes beta-2-microglobulin, BTP beta-trace protein, eGFR estimated glomerular filtration rate, KDIGO Kidney Disease: Improving Global Outcomes, LMWPs low-molecular-weight proteins, mGFR measured glomerular filtration rate, and NA not applicable.