Table 3.
Accuracy of Current and New Approaches for GFR Estimation as Compared with Measured GFR in the Validation Data Set.
| Filtration Marker and Equation* | Black Participants | Non-Black Participants | Difference between Black Participants and Non-Black Participants (95% CI)† |
|---|---|---|---|
| Bias: Median Difference between Measured GFR and eGFR (95% CI)‡ | |||
| milliliters per minute per 1.73 square meters | |||
| Creatinine | |||
| eGFRcr(ASR), current | −3.7 (−5.4 to −1.8) | −0.5 (−0.9 to 0.0) | −3.2 (−5.0 to −1.3) |
| eGFRcr(ASR-NB), new | 7.1 (5.9 to 8.8) | −0.5 (−0.9 to 0.0) | 7.6 (6.1 to 9.0) |
| eGFRcr(AS), new | 3.6 (1.8 to 5.5) | −3.9 (−4.4 to −3.4) | 7.6 (5.6 to 9.5) |
| Cystatin C | |||
| eGFRcys(AS), current | −0.1 (−1.5 to 1.6) | 0.7 (0.2 to 1.2) | −0.8 (−2.5 to 0.8) |
| Creatinine–cystatin C | |||
| eGFRcr-cys(ASR), current | −2.5 (−3.7 to −1.2) | −0.6 (−0.9 to −0.2) | −1.9 (−3.2 to −0.6) |
| eGFRcr-cys(ASR-NB), new | 3.4 (1.5 to 4.5) | −0.6 (−0.9 to −0.2) | 4.0 (2.6 to 5.3) |
| eGFRcr-cys(AS), new | 0.1 (−0.9 to 1.6) | −2.9 (−3.3 to −2.5) | 3.0 (1.6 to 4.4) |
| Agreement within 30% of Measured GFR (P30)§ | |||
| percent | percentage points | ||
| Creatinine | |||
| eGFRcr(ASR), current | 85.1 (82.2 to 87.9) | 89.5 (88.5 to 90.4) | −4.4 (−7.6 to −1.2) |
| eGFRcr(ASR-NB), new | 86.4 (83.4 to 89.1) | 89.5 (88.5 to 90.4) | −3.1 (−6.2 to 0) |
| eGFRcr(AS), new | 87.2 (84.5 to 90.0) | 86.5 (85.4 to 87.6) | 0.7 (−2.4 to 3.8) |
| Cystatin C | |||
| eGFRcys(AS), current | 84.6 (81.7 to 87.6) | 88.9 (87.9 to 89.9) | −4.3 (−7.5 to −1.1) |
| Creatinine–cystatin C | |||
| eGFRcr-cys(ASR), current | 88.6 (85.8 to 91.2) | 92.4 (91.5 to 93.2) | −3.8 (−6.7 to −0.9) |
| eGFRcr-cys(ASR-NB), new | 90.8 (88.4 to 93.1) | 92.4 (91.5 to 93.2) | −1.6 (−4.2 to 1) |
| eGFRcr-cys(AS), new | 90.5 (88.1 to 92.9) | 90.8 (89.9 to 91.8) | −0.3 (−3.0 to 2.4) |
| Percent Agreement between eGFR and Measured GFR Categories¶ | |||
| Creatinine | |||
| eGFRcr(ASR), current | 63.2 (59.3 to 67.1) | 68.5 (67.0 to 70.1) | −5.3 (−9.6 to −1) |
| eGFRcr(ASR-NB), new | 59.2 (55.2 to 63.2) | 68.5 (67.0 to 70.1) | −9.3 (−13.7 to −4.9) |
| eGFRcr(AS), new | 61.8 (57.9 to 65.8) | 66.7 (65.1 to 68.2) | −4.9 (−9.3 to −0.5) |
| Cystatin C | |||
| eGFRcys(AS), current | 62.5 (58.6 to 66.5) | 66.1 (64.5 to 67.7) | −3.6 (−8.0 to 0.8) |
| Creatinine–cystatin C | |||
| eGFRcr-cys(ASR), current | 67.9 (64.1 to 71.7) | 70.8 (69.3 to 72.4) | −2.9 (−7.1 to 1.3) |
| eGFRcr-cys(ASR-NB), new | 66.5 (62.6 to 70.3) | 70.8 (69.3 to 72.4) | −4.3 (−8.6 to 0) |
| eGFRcr-cys(AS), new | 68.4 (64.6 to 72.2) | 70.2 (68.6 to 71.7) | −1.8 (−6 to 2.4) |
The equations are referred to by the filtration marker or markers (creatinine [eGFRcr], cystatin C [eGFRcys], or creatinine–cystatin C [eGFRcrcys]) and the demographic factors (age, sex, and race [ASR] or age and sex [AS]) that were used in their development. Non-Black (NB) refers to equations in which the Black race coefficient was removed.
Difference between race groups was defined as the metric in Black participants minus non-Black participants. A negative sign for difference in bias indicates underestimation of measured GFR in Black participants relative to non-Black participants. A negative sign for P30 or GFR category agreement indicates less agreement in Black participants as compared with non-Black participants. Differences for agreement within 30% of measured GFR and for percent agreement between eGFR and measured GFR categories are expressed as percentage points.
Bias is defined as the median difference between measured GFR and eGFR. A positive sign indicates underestimation of measured GFR, and a negative sign indicates overestimation of measured GFR.
P30 is the proportion of eGFR within 30% of measured GFR.
Correct classification refers to agreement between measured GFR and eGFR categories of more than 90, 60 to 89, 45 to 59, 30 to 44, 15 to 29, and less than 15 ml per minute per 1.73 m2.