Longitudinal Evaluation of Retinopathy of Prematurity Rates and Severity in India

Abstract

Purpose : The epidemiology of retinopathy of prematurity (ROP) changes over time as neonatal care improves across neonatal care units (NCUs). Prior work using an artificial intelligence (AI)-derived vascular severity scale (VSS) demonstrated that NCU-level ROP could be used for epidemiological monitoring and was associated with oxygen management in 13 NCUs in South India. In this study, we evaluated the change in NCU-level ROP severity over time in seven of these NCUs.

Methods : As part of the Aravind ROP tele-screening program, a VSS was derived from retinal fundus images collected during the first eye exam from babies screened at two different time periods: 2015–2017 and 2019–2020. Differences in VSS were evaluated using a one- or two-way analysis of covariance (ANCOVA) to control for gestational age (GA) or GA and NCU, respectively. The proportion of babies diagnosed with ROP was evaluated using a test of equal proportions.

Results : Between the two time periods studied, the proportion of babies diagnosed with ROP decreased across all NCUs from 32% (range: 7.0% – 75.0%) in the earlier time period to 11% (range: 7.1% – 13.1%, p < 0.001) in the later period. This was associated with an increase in mean birthweight and gestational age (Table). However, when controlling for GA, there was no clinically meaningful change in the mean ROP severity as assessed by the VSS (2.9 to 3.0), although this varied significantly by NCU and GA. The figure demonstrates the changes in one NCU, with lower VSS in babies born after 31 weeks and higher VSS (and more babies surviving to point of screening) in babies born before 31 weeks.

Conclusions : On average NCUs in South India are screening more babies for ROP now than five years ago, which may in part be due to improved survival especially in the youngest cohort as well as increased awareness of ROP among pediatricians and improvements in NCU care. The NCU-level VSS did not change at the population level but varied at the NCU level due to changes in demographics in each population, with higher VSS in the youngest babies being offset by many low-risk older babies with no disease.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

Figure: ROP screening exams at select NCU. An increase in mean VSS at this NCU (D) over time masked changes in disease epidemiology, with lower ROP severity in older babies and apparently improved survival in younger babies.

 

Table: Patient demographics.