Derivation and external validation of the prognostic rule for respiratory insufficiency and death
| Variable | c-statistic (95% CI) | Sensitivity % (95% CI) | Specificity % (95% CI) | PPV % (95% CI) | NPV % (95% CI) |
| Respiratory insufficiency | |||||
| Derivation | 0.86 (0.84–0.89) | 83 (71–91) | 81 (72–89) | 77 (65–86) | 86 (77–93) |
| External validation | 0.74 (0.72–0.75) | 53 (51–55) | 82 (81–83) | 62 (60–64) | 76 (75–77) |
| Death | |||||
| Derivation | 0.84 (0.80–0.89) | 83 (63–95) | 81 (73–87) | 46 (30–61) | 96 (91–99) |
| External validation | 0.72 (0.71–0.74) | 47 (44–50) | 82 (81–83) | 36 (34–38) | 88 (87–89) |
PPV: positive predictive value; NPV: negative predictive value. Sensitivity, specificity, PPV and NPV were based on the following cut-off points: respiratory insufficiency ≥0.45 and death ≥0.11.