P2C312: A Study on Incidence of and Risk Factors for Retinopathy of Prematurity Requiring Treatment

Background: The study was carried out in a tertiary care (level III NICU) center situated in a metropolitan city in India, Mumbai. It was an observational cohort study with two arms. For the retrospective arm, eligible premature babies admitted in the institution from 1st October 2019 to 31st December 2020 were recruited. For the prospective arm, eligible premature babies admitted to the hospital from 1st January 2021 to 31st March 2021 were recruited after obtaining written informed consent from one of the parents. They were followed up till 42 weeks of gestation.

Methods: Descriptive statistics was used to assess infant characteristics. Mean (SD) and Median (IQR) were used to analyze normally distributed and non-parametric data, respectively. Fisher Exact test (categorical data) was used to assess the impact of various risk factors on the incidence and severity of ROP. P value of less than 0.05 was considered as significant. Logistic regression was performed to determine factors that were significant in univariate analysis and check which were significant on multivariate analysis.

Results: 127 (44.09%) of the enrolled infants developed ROP. The proportion of babies developing ROP requiring treatment was found to be 14.93% in the study population. The proportion of infants born before 30 weeks of gestation developing ROP was higher than that of infants born at 30 weeks or above. 43 (14.93%) infants developed ROP that required treatment. The commonest site for development of ROP was zone 2 (85, 66.92%) followed by zone 3 (34, 26.77%). There was a significant difference between gestational age and birth weight of infants requiring treatment and others. In addition, the duration of respiratory support was significantly different between these two groups. Among the post-natal risk factors studied, several factors such as SGA status, resuscitation at birth, ventilation, CPAP, supplemental oxygen via nasal prongs/free flow, duration respiratory support, presence of sepsis, thrombocytopenia, excessive weight gain and pRBC transfusion were found to be significantly associated with ROP requiring treatment in univariate analysis. Similarly, maternal factors such as maternal anemia, premature rupture of membranes (PROM) and detection of abnormalities on Doppler studies were found to be significant. However, on multi-variate logistic regression, the only factors that were requirement of resuscitation (either with 100% oxygen or blended oxygen), requirement of mechanical ventilation, SGA status and maternal anemia. Lower the birth weight or lower the gestational age at birth, higher is the incidence of ROP.

Conclusion: Our study has evaluated certain factors that are scarcely evaluated for association with ROP requiring treatment: inappropriate weight gain, SGA- status, abnormalities on Doppler study done in pregnancy and maternal anemia. Preterm, VLBW infants who required resuscitation, respiratory support are at highest risk of developing ROP and hence should be screened for the development of severe ROP.