Table 3 The sensitivity, positive predictive value (PPV) at various decision threshold for the five models using the EPDS/GAD/PRES predictors. The decision threshold is the value at which women predicted to have a risk greater or equal to are classified as ‘will have depression’ by the prediction model. When implementing a model for decision support, a suitable decision threshold needs to be determined based on the required sensitivity/PPV
Sensitivity | Trimester 1 | Trimester 2 | Trimester 3 | After delivery 1 | After delivery 2 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Threshold | % > = threshold | PPV (%) | Threshold | % > = threshold | PPV (%) | Threshold | % > = threshold | PPV (%) | Threshold | % > = threshold | PPV (%) | Threshold | % > = threshold | PPV (%) | |
10% | 0.80 | 2.9 | 75.0 | 0.65 | 4.0 | 52.4 | 0.70 | 4.1 | 60.9 | 0.54 | 5.1 | 33.3 | 0.58 | 3.9 | 45.0 |
20% | 0.66 | 6.1 | 67.6 | 0.54 | 8.3 | 50.0 | 0.60 | 8.5 | 59.6 | 0.45 | 7.9 | 40.5 | 0.42 | 9.3 | 37.5 |
30% | 0.52 | 10.3 | 61.4 | 0.43 | 13.4 | 46.5 | 0.51 | 13.2 | 57.5 | 0.39 | 11.5 | 42.6 | 0.33 | 14.8 | 35.5 |
40% | 0.44 | 13.7 | 60.5 | 0.34 | 19.3 | 43.1 | 0.43 | 18.7 | 53.8 | 0.30 | 18.3 | 36.0 | 0.26 | 22.3 | 31.3 |
50% | 0.32 | 21.3 | 49.2 | 0.27 | 25.8 | 41.1 | 0.37 | 25.6 | 49.3 | 0.25 | 24.1 | 34.5 | 0.21 | 28.9 | 29.5 |
60% | 0.25 | 28.0 | 45.2 | 0.21 | 35.6 | 35.6 | 0.30 | 32.8 | 46.2 | 0.21 | 30.7 | 31.9 | 0.17 | 36.1 | 28.5 |
70% | 0.18 | 36.1 | 40.5 | 0.15 | 46.0 | 32.0 | 0.22 | 43.2 | 40.8 | 0.17 | 38.2 | 30.2 | 0.15 | 41.6 | 29.0 |
80% | 0.13 | 49.8 | 33.7 | 0.12 | 56.6 | 29.8 | 0.14 | 55.1 | 36.6 | 0.12 | 47.3 | 27.9 | 0.11 | 50.9 | 27.1 |
90% | 0.07 | 69.0 | 27.2 | 0.08 | 72.2 | 26.2 | 0.10 | 68.3 | 33.2 | 0.07 | 59.3 | 24.8 | 0.07 | 66.2 | 23.5 |