Table 2

Specificity with 95% CI for 100% sensitivity at birth and over postnatal weeks for model development group (N=6991), and external validation groups (N=1241)

Model development group (DevGroup)*External validation (ValGroups)†
Specificity (95% CI)
N=6991
Specificity (95% CI)
N=1241
At birth53.1 (51.9 to 54.3)46.3 (43.4 to 49.2)
Cumulatively at PNA 6 weeks53.3 (52.0 to 54.5)46.4 (43.5 to 49.3)
Cumulatively at PNA 7 weeks54.2 (53.0 to 55.4)47.2 (44.4 to 50.1)
Cumulatively at PNA 8 weeks60.5 (59.3 to 61.7)53.5 (50.6 to 56.4)
Cumulatively at PNA 9 weeks67.6 (66.5 to 68.7)61.2 (58.3 to 63.9)
Cumulatively at PNA 10 weeks72.1 (71.0 to 73.2)65.9 (63.1 to 68.5)
Cumulatively at PNA 11 weeks75.3 (74.3 to 76.4)69.3 (66.6 to 71.9)
Cumulatively at PNA 12 weeks75.5 (74.5 to 76.5)69.6 (66.9 to 72.2)
Cumulatively at PNA 13 weeks80.6 (79.6 to 81.5)75.2 (72.6 to 77.6)
Cumulatively at PNA 14 weeks80.6 (79.7 to 81.6)75.2 (72.6 to 77.6)
  • Model development group includes data from SWEDROP, born at GA of 24–30 weeks (2007–2017).

  • Validation groups consist of four external validation cohorts, one from Sweden (later time period than in model development group), one from Germany and two from USA.

  • Cumulative specificity at a certain PNA is calculated as a union of specificities up to and including that certain PNA.

  • *Cut-offs selected in model development group for sensitivity 100%.

  • †For validation groups, cut-offs obtained from model development group are applied. Sensitivity 100% for all postnatal weeks except for one infant at birth, and PNA 6 and 7 weeks (sensitivity 48/49 at those time points), with severe comorbidity profile.

  • GA, gestational age; PNA, postnatal age; ROP, retinopathy of prematurity; SWEDROP, Swedish National Registry for ROP.