Blood neutrophil-to-lymphocyte ratio as a risk factor in treatment for retinopathy of prematurity

Purpose To investigate the blood neutrophil-to-lymphocyte ratio (NLR) as a risk factor for retinopathy of prematurity (ROP) development or treatment. Methods Retrospective cohort study. Infants who underwent ROP screening at Shiga University of Medical Science Hospital and Omihachiman Community Medical Center between April 2010 and December 2021 were included in this study. Screening criteria were gestational age (GA) < 32 weeks or birth weight (BW) < 1500 g. Multivariate logistic regression analysis was applied to investigate whether the NLR constituted an independent risk factor for ROP development or treatment. The objective variable was ROP development or treatment, and the explanatory variables were GA, BW, NLR, maternal infection or clinical chorioamnionitis and corticosteroid use by the mother. Maternal infection or clinical chorioamnionitis and corticosteroid use by the mother was included in the explanatory variables to adjust for factors affecting the NLR. Results In total, 220 infants met the inclusion criteria, of whom 125 developed ROP, whereas 95 infants did not display ROP. GA was significantly associated with ROP development (odds ratio (OR): 0.41, p < 0.001); however, the NLR was not significantly associated with ROP development (OR: 1.0, p = 0.74). Thirty-eight infants received treatment for ROP, whereas 182 infants had no such treatment. BW and the NLR were significantly associated with ROP treatment (OR: 1.6 and 0.66, p < 0.001 and 0.003, respectively). Conclusion The NLR was not a risk factor for ROP development but was a risk factor for ROP treatment.