NEDROP 2 population characteristics
| Screened for ROP | No ROP | Overall ROP | Mild ROP | Severe ROP | |
| A. The NEDROP 2 study population | 1085 | 780 | 305 | 256 | 49 |
| GA* | 29.0 (27.3–30.4) | 29.6 (28.3–30.9) | 27.1 (26.0–28.7) | 27.6 (26.3–28.9) | 25.7 (24.9–26.6) |
| BW* | 1150 (935–1350) | 1213 (1029–1414) | 938 (760–1150) | 975 (800–1178) | 750 (319-865) |
| Multiple pregnancy, n (%) | 278 (25.6) | 192 (24.6) | 86 (28.1) | 78 (30.5) | 8 (16.3) |
| B. Screening | |||||
| Examinations per patient | 3 (2–4) | 2 (1–3) | 5 (3–7) | 4 (3–6) | 9 (8–11) |
| First exam PMA | 34.4 (32.9–36.0) | 35.0 (33.6–36.4) | 32.6 (31.7–34.1) | 33.0 (31.9–34.3) | 31.9 (31.2–33.1) |
| First exam PNA | 5.4 (5.0–6.0) | 5.3 (5.0–5.9) | 5.6 (5.0–6.1) | 5.4 (5.0–6.0) | 6.1 (5.6–6.9) |
| Timely, n (%) | 849 (78.2) | 599 (76.8) | 250 (82.0) | 211 (82.4) | 39 (79.6) |
| Too late, n (%) | 236 (21.8) | 181 (23.2) | 55 (18.0) | 45 (17.6) | 10 (20.4) |
| C. ROP, median (IQR) | |||||
| First detection PMA | NA | NA | 34.1 (33.0–35.7) | 34.3 (33.0–35.9) | 33.6 (32.1–34.6) |
| First detection PNA | NA | NA | 6.7 (5.4–8.3) | 6.6 (5.3–8.0) | 7.3 (6.5–9.1) |
Mild ROP: stages 1–2, severe ROP: stages ≥3.
*t-test no ROP versus overall ROP, p<0.001.
BW, birth weight; GA, gestational age; NA, not applicable; PMA, postmenstrual age; PNA, postnatal age; ROP, retinopathy of prematurity.