Table 2 Retinopathy of prematurity stage ⩾3 and those treated by gestational age groups and time epoch. Values are n/N (%).
| Gestational age | 1992–94 | 1995–97 | 1998–2000 | 2000–02 |
|---|---|---|---|---|
| 22–24 weeks | ||||
| Stage ⩾3 | 17/41 (41.5)* | 16/53 (30.2) | 23/55 (41.8) | 41/76 (53.9)‡ |
| Treated/survived | 8/41 (19.5)* | 9/53 (17.0) | 15/55 (27.3) | 25/76 (32.9)‡ |
| Treated/stage ⩾3 | 8/17 (47.1)† | 9/16 (56.3) | 15/23 (65.2) | 25/41(61.0) |
| 25–26 weeks | ||||
| Stage ⩾3 | 55/210 (26.2) | 56/268 (20.9) | 41/249 (16.5)†† | 46/238 (19.3)¶ |
| Treated/survived | 19/210 (9.0) | 21/268 (7.8) | 24/249 (9.6) | 32/238 (13.4) |
| Treated/stage ⩾3 | 19/55 (34.5) | 21/56 (37.5) | 24/41 (58.5)†† | 32/46 (69.6)§†† |
| 27–29 weeks | ||||
| Stage ⩾3 | 30/729 (4.1) | 15/737 (2.0)** | 19/747 (2.5) | 17/707 (2.4) |
| Treated/survived | 14/729 (1.9) | 7/737 (0.9) | 8/747 (1.1) | 8/707 (1.1) |
| Treated/stage ⩾3 | 14/30 (46.7) | 7/15 (46.7) | 8/19 (42.1) | 8/17 (47.1) |
All results are expressed total survivors unless indicated.
*Stage ⩾3/survived (percent with stage ⩾3) or treated/survived (percent treated); †treated/stage ⩾3 (percent treated).
‡Significant trend to increased stage ⩾3 and treated (p = 0.052 and p<0.05, respectively); ¶significant trend to decreased stage ⩾3 (p<0.05); §significant trend to increased treated of those who developed stage ⩾3 (p<0.001); **significantly different from 1992–94 epoch (p<0.05) and ††(p<0.02).