Table 2.
Performance of different measured GFR sampling combinations compared with reference mGFR calculation
| Performance Measure | R-mGFR (120–240 min) | F4-mGFR (60–150 min) | F5-mGFR (60–180 min) | M4-mGFR (90–180 min) | M5-mGFR (90–210 min) |
|---|---|---|---|---|---|
| Mean mGFR±SD, ml/min per 1.73 m2 | 102.3±13.7 | 101.9±12.7 | 101.3±12.7 | 101.9±13.2 | 101.6±13.5 |
| Median bias (95% CI), ml/min per 1.73 m2 | — | −0.4 (−1.1 to 0.6) | −0.7 (−1.2 to −0.3) | −0.4 (−0.5 to −0.1) | −0.5 (−0.8 to −0.1) |
| Precision: IQR of bias (95% CI), ml/min per 1.73 m2 | — | 2.4 (1.6 to 3.1) | 1.9 (0.9 to 3.1) | 1.2 (0.5 to 1.6) | 1.4 (0.9 to 1.9) |
| MAE (95% CI), ml/min per 1.73 m2 | — | 1.5a (1.2 to 1.9) | 1.5a (1.2 to 1.9) | 0.9 (0.8 to 1.2) | 0.9b (0.7 to 1.2) |
| P5 (%) | — | 100 | 100 | 100 | 100 |
| P2 (%) (95% CI) | — | 74 (61 to 86) | 74 (61 to 86) | 86 (74 to 95) | 88 (79 to 98) |
Bias is defined as median (95% confidence interval) difference between the reference measured GFR and sampling combination. Precision is defined as the interquartile range (95% confidence interval) of the bias. Mean absolute error is defined as the absolute mean (95% confidence interval) difference between the reference mGFR and sampling combination. P5/P2 are the percentage of shorter measured GFRs within 5% and 2% of the reference measured GFR. CI, confidence interval; IQR, interquartile range; MAE, mean absolute error; mGFR, measured GFR; P5, percentage within 5%; R-mGFR, reference mGFR.
P < 0.001 compared with M4-mGFR.
P = 0.203 compared with M4-mGFR.