Association between Hematocrit in the First Two Hours of Life and Retinopathy during Prematurity: A Retrospective Study from DRYAD

Introduction: Our study investigated the association between hematocrit in the first two hours (HCT2h) of life and retinopathy of prematurity (ROP). Methods Data were obtained from an observational study of the DRYAD database. The study was conducted at the Santa Clara Valley Medical Center (SCVMC). Data on preterm babies whose gestational age (GA) was < 34 weeks were collected prospectively from January 2008 to February 2014. Logistic regression was applied to explore the association between HCT2h and ROP. Results A total of 326 very preterm infants born at or earlier than 34 weeks were included. The incidence of any ROP was 23.9%, and the incidence of severe ROP was 4.6%. The HCT2h, birth weight, GA, Apgar1 min, and Apgar5 min of any ROP group were significantly lower than those of preterm babies without ROP (p < 0.001). Sex differences, the rate of multiples, and delivery mode between the two groups were not statistically significant (p > 0.05). We classified HCT2h into three levels, and after multivariate logistic regression, we found that high HCT2h remained a significant protective factor against ROP (p < 0.001). Through subgroup analysis, we observed that among preterm infants with a GA of 28 weeks or more, there was a significant inverse association between a 1% increase in HCT2h and a 17% reduction in the occurrence of ROP. Conclusion We found that a greater HCT2h was associated with a lower incidence of ROP among preterm infants born between 28 and 34 weeks of gestation. Trial registration: This was a retrospective study and the data were from the DRYAD database. Santa Clara Valley Medical Center’s (SCVMC) ethical committee reviewed and approved the studies involving human participants. The participants provided their written informed consent to participate in this study. We did not perform any extra interventions.