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Table 4 Prognostic accuracy of delivery within 7 days at various cut-off points of predicted probability

From: Timing of delivery in a high-risk obstetric population: a clinical prediction model

Predicted probability (%)

<15.0a

<27.0

<50.0

<65.0

Number of women

233

510

1410

2528

N women delivered at ≤7 days (N = 1473 overall)

14

56

440

1108

N women delivered at >7 days (N = 1539 overall)

219

454

970

1420

Sensitivity

99.1% (98.4–99.4)

96.2% (95.1–97.1)

70.1% (67.7–72.4)

24.8% (22.6–27.1)

Specificity

14.2% (12.6–16.1)

29.5% (27.3–31.8)

63.0% (60.0–65.4)

92.3% (90.8–93.5)

False positive rate

85.8% (83.9–87.4)

70.5% (68.2–72.7)

37.0% (34.6–40.0)

7.7% (6.4–9.2)

False negative rate

0.9% (0.6–1.6)

3.8% (2.9–4.9%)

29.9% (27.6–32.3)

75.2% (72.9–77.4)

Positive predictive value

52.5% (50.6–54.4)

56.6% (54.7–58.6)

64.5% (62.1–66.8)

75.4% (71.4–79.0)

Negative predictive value

94.0% (90.2–96.4)

89.0% (86.0–91.5)

68.9% (66.3–71.2)

56.2% (54.2–58.1)

Positive likelihood ratio

1.16 (1.13–1.18)

1.37 (1.32–1.41)

1.90 (1.76–2.04)

3.93 (3.15–4.91)

Negative likelihood ratio

0.07 (0.04–0.11)

0.13 (0.10–0.17)

0.47 (0.43–0.52)

0.82 (0.79–0.84)

  1. ae.g., if women with predicted probability <15% were considered at low-risk of delivery within 7 days, the sensitivity of the prognostic tool would be 99.1% while the specificity would be 14.2