Table 4.
Sensitivity and specificity of SLPI as a biomarker for AKI at optimal cut-off values.
| Time Point after Surgery | Optimal Cut-off (ng/mL) | Sensitivity (%) | 95% CI | Specificity (%) | 95% CI | Likelihood Ratio | Youden Index |
|---|---|---|---|---|---|---|---|
| Development cohort, Serum SLPI | |||||||
| 6 h | >85.20 | 64.3 | 35.1–87.2 | 68.29 | 51.9–81.9 | 2.027 | 0.32 |
| 12 h | >92.72 | 66.7 | 34.9–90.1 | 73.17 | 57.1–85.8 | 2.485 | 0.39 |
| 24 h | >87.93 | 100.0 | 75.3–100.0 | 54.55 | 38.9–69.6 | 2.200 | 0.54 |
| Validation cohort, Serum SLPI | |||||||
| 24 h | >101.8 | 70.0 | 45.7–88.1 | 67.6 | 57.8–76.4 | 2.162 | 0.38 |
| 48 h | >78.45 | 77.8 | 52.4–93.6 | 71.2 | 61.4–79.9 | 2.709 | 0.49 |
Optimal cut-off concentrations were calculated with the help of the Youden index; CI, confidence interval; Pre-OP, before surgery; SLPI, secretory leukocyte protease inhibitor.