Hemoglobin Levels May Predict Retinopathy of Prematurity Development

Credit: Carlo Navarro/Unsplash

Higher hemoglobin (Hb) levels during early postnatal days may be protective against the development of retinopathy of prematurity (ROP) in preterm infants, according to a recent retrospective cohort study.¹

Incidence of ROP was nearly 30% among preterm infants born before 34 weeks of gestational age. A lower birth weight, lower Hb during early postnatal days, presence of respiratory distress syndrome (RDS), and required packed red blood cell (PRBC) transfusion were each independently linked to ROP development.

“This study emphasizes the implementation of optimum antenatal care to avoid premature delivery, antenatal steroid use to reduce RDS burden, the practice of delayed cord clamping, and frequent phlebotomy to avoid iatrogenic anemia, which may reduce ROP development in preterm infants,” wrote the investigative team, led by Santosh K. Panda, MD, department of pediatrics, Kalinga Institute of Medical Sciences.

A leading cause of visual morbidity in preterm infants, ROP’s prevalence has ranged from 9.3% to nearly 37% among very low-birth-weight neonates or those born <32 weeks, across various nationwide surveys.² Demographic characteristics, including gestational age, birth weight, and neonatal morbidities, are established links to ROP and help clinicians classify preterm infants for ROP screening.³

However, given the disease’s notable, increasing burden, the search for new biomarkers is critical to predict ROP progression and enact prevention strategies in preterm infants. Panda and colleagues hypothesized a correlation between alterations in major complete blood count (CBC) parameters and the pathway of neovascularization in ROP.¹

This retrospective study was performed in a neonatal intensive care unit in India from January 2018 to June 2019. All preterm babies born <34 weeks gestational age admitted to the neonatal unit within 48 hours of age were included for analysis. Hematology parameters of CBC conducted in that 48-hour period, demographic characteristics, neonatal morbidities, and ROP screening results on preterm neonates were assessed by the team.

A multivariate logistic regression model was built for the independent prediction of ROP development. Confounding variables initialy identified in univariate analysis were included as the covariate in the multivariate logistic regression model to control for their effect.

Across the study period, 167 preterm neonates were initial CBC report within 48 hours of life were included for analysis. After exclusions were applied, 148 study participants remained, of which 43 (29%) had any stage of ROP: Stage 1 (n = 26), Stage 2 (n = 8), and Stage 3 (n = 9).

Multivariate regression model analysis revealed independent risk factors linked to ROP development, including birth weight (adjusted odds ratio [aOR], 0.003; 95% CI, 0.00 – 0.11), Hb level (aOR, 0.70; 95% CI, 0.54–0.90), RDS presence (aOR, 7.61; 95% CI, 1.5 – 36.39), and need for PRBC transfusion (aOR, 4.26; 95% CI, 1.1 – 16.44).

Importantly, the mean Hb levels were significantly lower in neonates with ROP (16.32 g/dL) compared with neonates without ROP (17.82 g/dL) (P = .002). Data showed the risk of ROP development was higher among neonates with initial Hb 10.5–15.4 g/dL (OR, 3.7 [95% CI, 1.5 – 8.9]; P = .003) and 15.4 – 17.3 g/dL (OR, 2.5 [95% CI, 1.01 – 6.16]; P = .047), compared with neonates with initial Hb of >17.3 g/dL.

In their summary, Panda and colleagues indicated the presence of anemia at birth could have been secondary to various antenatal comorbidities that affected the incidence of ROP, requiring further study on the relationship.

“The study has major implications for middle-income countries, where the third epidemic of ROP has emerged,” they wrote. “It could help the clinicians triage the preterm infant based on the early Hb level, and neonates with an early lower Hb level are prioritized for ROP screening.”

References

1. _{Gudu RK, Sahoo S, Jena P, Behura SS, Priyadarshini S, Panda SK. Lower Hemoglobin Levels as a Risk Factor for the Development of Retinopathy of Prematurity. Cureus. 2024;16(7):e64264. Published 2024 Jul 10. doi:10.7759/cureus.64264}
2. _{Hong EH, Shin YU, Cho H. Retinopathy of prematurity: a review of epidemiology and current treatment strategies. Clin Exp Pediatr. 2022;65(3):115-126. doi:10.3345/cep.2021.00773}
3. _{Kim SJ, Port AD, Swan R, Campbell JP, Chan RVP, Chiang MF. Retinopathy of prematurity: a review of risk factors and their clinical significance. Surv Ophthalmol. 2018;63(5):618-637. doi:10.1016/j.survophthal.2018.04.002}