Infants’ characteristics at birth, first sign of ROP, maximum stage and ROP treatment (Swedish Contemporary Validation Cohort 2018–2020)
| Variable | Total (n=1082*) | No ROP treatment (n=1025) | ROP treatment (n=57) |
| Sex | |||
| Boy | 598 (55.3%) | 570 (55.6%) | 28 (49.1%) |
| Girl | 484 (44.7%) | 455 (44.4%) | 29 (50.9%) |
| Gestational age at birth (weeks) | 28.2 (1.9) | 28.3 (1.8) | 25.3 (1.1) |
| Gestational age (full weeks) | |||
| 24 | 71 (6.6%) | 44 (4.3%) | 27 (47.4%) |
| 25 | 99 (9.1%) | 83 (8.1%) | 16 (28.1%) |
| 26 | 131 (12.1%) | 124 (12.1%) | 7 (12.3%) |
| 27 | 154 (14.2%) | 148 (14.4%) | 6 (10.5%) |
| 28 | 165 (15.2%) | 164 (16.0%) | 1 (1.8%) |
| 29 | 247 (22.8%) | 247 (24.1%) | 0 (0.0%) |
| 30 | 215 (19.9%) | 215 (21.0%) | 0 (0.0%) |
| Birth weight (g) | 1117 (340) | 1142 (329) | 667 (185) |
| Birth weight SDS | −1.11 (1.46) | −1.08 (1.41) | −1.75 (1.98) |
| Maximum ROP stage | |||
| No ROP | 744 (68.8%) | 744 (72.6%) | 0 (0.0%) |
| ROP stage 1 | 122 (11.3%) | 122 (11.9%) | 0 (0.0%) |
| ROP stage 2 | 107 (9.9%) | 104 (10.1%) | 3 (5.3%) |
| ROP stage 3 | 106 (9.8%) | 55 (5.4%) | 51 (89.5%) |
| ROP stage 4B | 3 (0.3%) | 0 (0.0%) | 3 (5.3%) |
| Postnatal weeks to first ROP diagnosis | 8.1 (6.9; 9.7) n=338 | 8.0 (6.6; 9.7) n=281 | 8.4 (7.6; 10.0) n=57 |
| Postnatal weeks to first ROP treatment | 12.6 (11.0; 13.6) | ||
| Number of ROP screening examinations | 5 (3; 8) | 4 (3; 7) | 17 (14; 22) |
| DIGIROP-Birth risk estimate (probability) | 0.006 (0.001; 0.045) | 0.005 (0.001; 0.033) | 0.239 (0.108; 0.321) |
For categorical variables, n (%) is presented.
For continuous variables, mean (SD) or median (IQR) are presented.
*882 infants originate from the SWEDROP for years 2018–2019, and 200 infants only from the Västra Götaland and Skåne regions for year 2020.
ROP, retinopathy of prematurity; SDS, SD score; SWEDROP, Swedish National Registry for ROP.