Risk factors in the development of mild and severe retinopathy of prematurity

PURPOSE To evaluate the risk factors in the development of mild and severe retinopathy of prematurity (ROP). METHODS All infants (n = 88) screened for ROP at a neonatal intensive care unit over a 2-year period with gestational age <= 34 weeks and follow-up of 43 weeks postconception were included. The findings were classified in accordance with the International Classification of Retinopathy of Prematurity. The study group was classified into three subgroups: group A included patients without retinopathy; group B included patients with stage 1 or 2 (mild-ROP); and group C included patients who progressed to moderate or severe stage 3 (severe-ROP) and were treated. A retrospective review of records was performed and statistical analysis of eight possible risk factors for ROP was evaluated by using logistic regression. RESULTS Logistic regression analysis showed birth weight (BW) (p = 0.019) and respiratory distress syndrome (p = 0.029) as independent significant risk factors for the development of stage 1 and 2 ROP, with BW (p < 0.0001) as an independent significant risk factor for the progression to stage 3 ROP. Total volume of blood transfusion and duration of artificial ventilation were also found to be risk factors with high rates of stage 3 ROP. In group C, BW <= 1000 g (p = 0.0002) and gestational age <= 28 weeks (p < 0.0001) were significant risk factors associated with higher rates of ROP. CONCLUSIONS This study showed BW and respiratory distress syndrome as independent risk factors in the development of mild ROP and BW in the development of severe ROP.