Evaluating the relationship of red cell distribution with retinopathy of prematurity

Background Retinopathy of prematurity (ROP) is one of the leading causes of childhood blindness that can be avoided. Its pathogenesis is linked to inflammation and oxidative stress. Red cell distribution width (RDW) is an easily obtainable hematological index which reflects the variability of different erythrocyte sizes and has been associated with inflammatory and hypoxic conditions. Aim To assess the relationship between RDW and ROP in preterm infants. Patients and methods A case-control study encompassed 70 preterm infants (<35 weeks’ gestation). During the first and second postnatal weeks, RDW was assessed, and ROP was ophthalmologically screened and classified according to international classification standards. Results ROP was diagnosed in 35 (50%) infants. There were no significant differences between infants with and without ROP regarding gestational age (30.7±2.3 vs. 31.0±2.0 weeks, P =0.654) or birth weight (1.59±0.42 vs. 1.54±0.34 kg, P =0.623). The occurrence of sepsis was higher in cases of ROP (80.0 vs. 51.4%, P =0.012). RDW was significantly higher in ROP infants at both week 1 (19.65±1.96 vs. 16.36±1.47 fL, P <0.001) and week 2 (19.11±1.00 vs. 15.37±1.52 fL, P <0.001). Receiver operating characteristic analysis showed excellent predictive accuracy for second-week RDW (AUC=0.983; 95% confidence interval: 0.962–1.00) at a cutoff of 17.9 fL (sensitivity 91.4%, specificity 94.3%). Conclusions Early postnatal RDW elevation is strongly associated with ROP and may serve as a simple, cost-effective biomarker for early risk identification in preterm infants.