Table 3.
Predictive ability of combinations of significant predictors
| Outcome | Characteristic (%) | Events (%) |
Percentage of events | Percentage correct | Sensitivity | Specificity | PPV | NPV | NNT 50 | NNT 33 | NNT 25 | AE 50 | AE 33 | AE 25 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Yes | No | ||||||||||||||
| ‘Medical’ complications n: 327 | Age ≥80 years (12.3) | 118 (11.9) | 872 | 36.1 | 86.5 | 36.09 | 88.67 | 0.12 | 0.97 | 17 | 25 | 34 | 59 | 39 | 30 |
| Walking aids (24.2) | 187 (9.6) | 1753 | 57.2 | 76.4 | 57.19 | 77.22 | 0.10 | 0.98 | 21 | 31 | 41 | 94 | 62 | 47 | |
| Hypertension (52.4) | 221 (5.3) | 3982 | 67.6 | 49.0 | 67.58 | 48.25 | 0.05 | 0.97 | 38 | 57 | 76 | 111 | 74 | 55 | |
| Anticoagulants (5.0) | 42 (10.5) | 357 | 12.8 | 92.0 | 12.84 | 95.36 | 0.11 | 0.96 | 19 | 29 | 38 | 21 | 14 | 11 | |
| Anaemia (12.4) | 94 (9.4) | 904 | 28.7 | 85.8 | 28.75 | 88.25 | 0.09 | 0.97 | 21 | 32 | 42 | 47 | 31 | 24 | |
| Psychological disorder (11.6) | 78 (8.4) | 851 | 23.9 | 86.3 | 23.85 | 88.94 | 0.08 | 0.96 | 24 | 36 | 48 | 39 | 26 | 20 | |
| Pulmonary disease (7.4) | 46 (7.7) | 551 | 14.1 | 89.6 | 14.07 | 92.84 | 0.08 | 0.96 | 26 | 39 | 52 | 23 | 15 | 12 | |
| ≥3 predictors (14.3) | 147 (12.9) | 996 | 45.0 | 85.3 | 44.95 | 87.05 | 0.13 | 0.97 | 16 | 23 | 31 | 74 | 49 | 37 | |
| ≥4 predictors (4.3) | 68 (19.8) | 275 | 20.8 | 93.3 | 20.80 | 96.43 | 0.20 | 0.97 | 10 | 15 | 20 | 34 | 23 | 17 | |
| ≥5 predictors (0.9) | 24 (32.4) | 50 | 7.3 | 95.6 | 7.34 | 99.35 | 0.32 | 0.96 | 6 | 9 | 12 | 12 | 8 | 6 | |
| ≥4 MP2 (18.1) | 174 (12.0) | 1276 | 53.2 | 82.2 | 53.21 | 83.42 | 0.12 | 0.98 | 17 | 25 | 33 | 87 | 58 | 44 | |
| ≥5 MP2 (12.8) | 139 (13.6) | 886 | 42.5 | 86.6 | 42.51 | 88.48 | 0.14 | 0.97 | 15 | 22 | 29 | 70 | 46 | 35 | |
| ≥2 MPEH (19.1) | 182 (11.9) | 1348 | 55.7 | 81.4 | 55.66 | 82.50 | 0.12 | 0.98 | 17 | 25 | 34 | 91 | 61 | 46 | |
| ≥3 MPEH2 (5.6) | 83 (18.5) | 366 | 55.7 | 92.4 | 25.38 | 95.14 | 0.18 | 0.97 | 11 | 16 | 22 | 42 | 28 | 21 | |
| ‘Severe medical’ complications n:213 | Age ≥80 years (12.3) | 70 (7.0) | 928 | 36.8 | 87.1 | 36.84 | 88.32 | 0.07 | 0.98 | 29 | 43 | 57 | 35 | 23 | 18 |
| Walking aids (24.2) | 108 (5.5) | 1861 | 56.8 | 76.1 | 56.84 | 76.57 | 0.05 | 0.99 | 36 | 55 | 73 | 54 | 36 | 27 | |
| Anticoagulants (4.9) | 27 (6.7) | 378 | 14.2 | 93.3 | 14.21 | 95.24 | 0.07 | 0.98 | 30 | 45 | 60 | 14 | 9 | 7 | |
| Psychological disorder (11.6) | 48 (5.1) | 895 | 25.3 | 87.2 | 25.26 | 88.73 | 0.05 | 0.98 | 39 | 59 | 79 | 24 | 16 | 12 | |
| Pulmonary disease (7.5) | 31 (5.11) | 577 | 16.3 | 90.9 | 16.32 | 92.73 | 0.05 | 0.98 | 39 | 59 | 78 | 16 | 10 | 8 | |
| ≥2 predictors (14.9) | 92 (7.6) | 1122 | 48.4 | 85.0 | 48.42 | 85.87 | 0.08 | 0.99 | 26 | 40 | 53 | 46 | 31 | 23 | |
| ≥3 predictors (3.1) | 31 (12.4) | 218 | 16.3 | 95.4 | 16.32 | 97.26 | 0.12 | 0.98 | 16 | 24 | 32 | 16 | 10 | 8 | |
| ≥4 predictors (0.3) | 6 (23.1) | 20 | 3.2 | 97.5 | 3.16 | 99.75 | 0.23 | 0.98 | 9 | 13 | 17 | 3 | 2 | 2 | |
| ≥3 MP (14.3) | 83 (7.3) | 1060 | 43.7 | 85.5 | 44.62 | 86.47 | 0.07 | 0.99 | 28 | 41 | 55 | 42 | 28 | 21 | |
| ≥4 MP2 (18.1) | 98 (7.0) | 1352 | 51.6 | 82.1 | 52.69 | 82.74 | 0.07 | 0.99 | 30 | 44 | 59 | 49 | 33 | 25 | |
| ≥2 MPEH (19.1) | 103 (6.7) | 1427 | 54.2 | 81.2 | 55.38 | 81.79 | 0.07 | 0.99 | 30 | 45 | 59 | 52 | 34 | 26 | |
Number of included patients is 8021 for ‘medical’ complications and 8132 for ‘severe medical’ complications due to 8.1% and 6.9% with missing data on relevant predictors.
AE 25, avoided events in the cohort with 25% event reduction; AE 30, avoided events in the cohort with 30% event reduction; AE 50, avoided events in the cohort with 50% event reduction; MP2, ‘medical’ predictors with two points if OR ≥1.9; MPEH, medical predictors excluding hypertension; MPEH2, ‘medical’ predictors excluding hypertension and two points if OR ≥1.9; NNT 25, number needed to treat if there is a 25% event reduction; NNT 30, number needed to treat if there is a 30% event reduction; NNT 50, number needed to treat if there is a 50% event reduction; NPN, negative predictive value; PPV, positive predictive value.