Table 3.
Predictive accuracy of GFR and secretory solute clearances for predicting kidney penciclovir clearance
| Predictor | MAE between Predicted and Measured Drug Clearance, ml/min | Difference in MAE Comparing iGFR with Secretory Clearance, ml/min (95% CI)a | MPE between Predicted and Measured Drug Clearance, % | Difference in MPE Comparing iGFR with Secretory Clearance, % (95% CI)a |
|---|---|---|---|---|
| iGFR | 53.9 | — | 24.1 | — |
| eGFRcreatinine | 67.5 | −13.6 (−25.7 to 0.1) | 29.8 | −5.7 (−11.9 to 0.3) |
| Secretion score | 41.1 | 12.8 (−1.8 to 25.1) | 18.0 | 6.1 (−1.3 to 12.9) |
| Individual clearance | ||||
| Pyridoxic acid | 51.0 | 2.9 (−11.6 to 16.6) | 22.0 | 2.1 (−5.8 to 12.7) |
| Isovalerylglycine | 54.5 | −0.6 (−16.7 to 18.3) | 26.7 | −2.6 (−11.2 to 8.5) |
| Tiglylglycine | 66.7 | −12.8 (−29.2 to 6.3) | 31.1 | −7.0 (−16.1 to 5.6) |
| Kynurenic acid | 57.0 | −3.1 (−17.2 to 14.6) | 25.8 | −1.7 (−11.6 to 9.4) |
| Xanthosine | 77.6 | −23.7 (−40.9 to −8.3) | 38.4 | −14.3 (−23.1 to −4.2)b |
| Cinnamoylglycine | 60.3 | −6.4 (−20.8 to 7.8) | 27.0 | −2.9 (−10.2 to 6.0) |
| Indoxyl sulfate | 61.7 | −7.8 (−19.8 to 5.1) | 29.2 | −5.1 (−11.7 to 1.2) |
| p-cresol sulfate | 49.2 | 4.7 (−7.4 to 18.2) | 22.0 | 2.1 (−3.8 to 6.5) |
iGFR was measured by iohexol disappearance. eGFR was on the basis of serum creatinine concentrations from the 2009 Chronic Kidney Disease Epidemiology Collaboration equation. MAE, mean absolute error; MPE, mean proportionate error.
a
The 95% CIs were derived using leave-one-out cross validation with bootstrap with 500 iterations. Positive values indicate greater agreement for secretory solute clearances, and negative values indicate greater agreement for iGFR.
b
Statistically significant adjusted correction for multiple comparisons using the Hommel method.