Table 5.
Classification matrix for the four mortality prediction systems
| Died | Survived | ||||||||
| System | PD | PS | PD | PS | Sensitivity | Specificity | PPV | NPV | OCCR |
| Cutoff 10% | |||||||||
| MPM II0 | 286 | 24 | 334 | 324 | 92 (87–95) | 49 (45–53) | 46 (42–50) | 93 (90–96) | 63 (60–66) |
| MPM II24 | 201 | 14 | 270 | 196 | 93 (89–96) | 42 (38–47) | 43 (38–47) | 93 (89–96) | 58 (55–62) |
| APACHE II | 206 | 9 | 278 | 188 | 96 (92–98) | 40 (36–45) | 43 (38–47) | 95 (92–98) | 58 (54–62) |
| SAPS II | 189 | 26 | 234 | 232 | 88 (83–92) | 50 (45–54) | 45 (40–50) | 90 (86–93) | 62 (58–65) |
| Cutoff 30% | |||||||||
| MPM II0 | 235 | 75 | 143 | 515 | 76 (71–80) | 78 (75–81) | 62 (57–67) | 87 (84–89) | 77 (75–80) |
| MPM II24 | 169 | 46 | 134 | 332 | 79 (73–84) | 71 (67–75) | 56 (50–61) | 88 (84–91) | 74 (70–77) |
| APACHE II | 161 | 54 | 107 | 359 | 75 (69–81) | 77 (73–81) | 60 (54–66) | 87 (83–90) | 76 (73–80) |
| SAPS II | 140 | 75 | 99 | 367 | 65 (58–71) | 79 (74–82) | 59 (52–65) | 83 (79–86) | 74 (71–78) |
| Cutoff 50% | |||||||||
| MPM II0 | 189 | 121 | 58 | 600 | 61 (55–66) | 91 (89–93) | 77 (71–82) | 83 (80–86) | 82 (79–84) |
| MPM II24 | 142 | 73 | 61 | 405 | 66 (59–72) | 87 (84–90) | 70 (63–76) | 85 (81–87) | 80 (77–83) |
| APACHE II | 110 | 105 | 53 | 413 | 51 (44–58) | 89 (85–91) | 67 (60–75) | 80 (76–83) | 77 (73–80) |
| SAPS II | 109 | 106 | 52 | 414 | 51 (44–58) | 89 (86–92) | 68 (60–75) | 80 (76–83) | 77 (73–80) |
Figures in parentheses are 95% confidence intervals. PD, predicted to die; PS, predicted to survive; PPV, positive predictive value; NPV, negative predictive value; OCCR, overall correct classification rate.