Complete blood count parameters to predict retinopathy of prematurity: when to evaluate and what do they tell us?

Purpose: To evaluate the relationship of novel inflammatory markers neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) with retinopathy of prematurity (ROP) development and requirement for laser photocoagulation (LP) treatment.

Methods: The charts of infants screened for ROP were reviewed retrospectively, and 120 newborns who had complete blood count (CBC) data in the first 24 hours after delivery (early period) and between 35 and 37th gestational weeks (late period) were included. Study population consisted of 34 infants who required LP for ROP treatment, 52 newborns with ROP that regressed without treatment, and 34 controls who did not developed any ROP stages. Demographics, etiological factors and CBC data including NLR and PLR values were noted. Risk factors for ROP development and treatment requirement were investigated using logistic regression analyses.

Results: Significantly lower NLR was found in ROP cases compared to non-ROP group during late period (p = 0.003), while there was no difference in NLR during early period (p = 0.298). No significant difference was observed in PLR during both early and late periods (p = 0.230 and p = 0.349, respectively). Multivariate analysis revealed daily weight gain as major risk factor for ROP development (p = 0.001; OR: 0.870, 95% CI: 0.799-0.947), and hyperbilirubinemia as an independent risk factor for LP requirement (p = 0.045; OR: 0.204, 95% CI: 0.043-0.966).

Conclusion: NLR or PLR does not appear to be predictive risk factors for treatment requirement in cases with ROP. CBC values during first 24 h of life may be misleading; therefore, a late period CBC is recommended to evaluate prognostic factors for ROP development.