Background and objective: Retinopathy of prematurity (ROP) develops mostly in very-low-birth-weight (VLBW) premature infants. Besides prematurity and hyperoxia, other variables have been brought up as risk factors for ROP. We aimed to search risk factors for ROP by comparing two groups of preemies, one with and the other without ROP.
Patients and methods: During 2004-2006, 27 VLBW premature infants developed ROP (ROP group). For each neonate in the ROP group, we chose a neonate born at similar gestational age (GA) (+/-1 week) but without ROP (control group). For each neonate of both groups, we recorded demographic, maternal, gestational, intrapartum, neonatal, interventional, growth and ophthalmologic data from patients' medical records.
Results: Eleven of the tested variables were significantly different between the ROP and control groups in univariate analysis. However, only seven of these variables remained significantly different between groups when controlling each variable for GA: bronchopulmonary dysplasia (BPD, p=0.04), duration of hospitalization (p=0.017), high-frequency oscillatory ventilation (HFOV, p=0.033), duration of oxygen therapy (p=0.023), surfactant therapy (p=0.045), inhaled steroids (p=0.015) and systemic steroids for BPD (p=0.007). These seven significant variables were related to respiratory morbidity and interventions. Multiple stepwise logistic regression including all significant variables in the univariate analysis showed that only systemic steroids remained significantly different between groups (p=0.007, OR 5.42, 95% CI 1.60-18.34).
Conclusion: Significantly more neonates in the ROP group received late postnatal systemic steroids as compared to controls. We speculate that steroids, by altering insulin growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF) expression, might contribute to the pathogenesis of ROP.