Adjusted OR (aOR) and 95% CI for blindness, adjusting for severe CP and grade 3 BPD (2006–2021 births)
| Risk factor | No cerebral injury | Cerebral injury* | ||
| Adjusted OR† (95% CI) | P value | Adjusted OR† (95% CI) | P value | |
| No severe ROP | 1.0 (reference group) | 3.72 (1.93 to 7.17) | <0.0001 | |
| Severe ROP‡ | 4.44 (2.57 to 7.67) | <0.0001 | 7.93 (3.61 to 17.4) | <0.0001§ |
*The marginal adjusted OR for any cerebral injury in the presence of severe ROP was 1.79 (95% CI 1.05 to 3.03), p=0.03.
†The adjusted ORs and p values are from a logistic regression model using GEE; the model adjusted for sex, birth weight, multiple birth, maternal race, cerebral injury, severe ROP, the interaction between cerebral injury and severe ROP, centre as a cluster effect, severe CP (GMFCS level 4 or 5) and grade 3 BPD (Jensen 2019 pragmatic definition). Multiplicative interaction between cerebral injury and ROP was found to be statistically significant (p=0.03).
‡The marginal adjusted OR for any severe ROP in the presence of cerebral injury was 2.13 (95% CI 1.45 to 3.13), p=0.0001.
§Compared with children with neither risk factor, the presence of both cerebral injury and severe ROP was associated with an adjusted OR of 7.93 (95% CI 3.61 to 17.4), p<0.0001. This comes from a logistic regression model assessing cerebral injury and severe ROP as a four-level variable (cerebral injury only, severe ROP only, both, neither) with no interaction term.
BPD, bronchopulmonary dysplasia; CP, cerebral palsy; GEE, generalised estimating equation; GMFCS, Gross Motor Function Classification System; ROP, retinopathy of prematurity.