Change in the incidence and severity of Retinopathy of Prematurity (ROP) in a Neonatal Intensive Care Unit in Northern India after 20 years: Comparison of two similar prospective cohort studies

Abstract

Purpose: To report the change in incidence and severity of retinopathy of prematurity (ROP) in the neonatal unit of a tertiary hospital after a 20-year period.

Methods: A prospective cohort study of one-year duration was conducted between July 2013 and June 2014 in the neonatal intensive care unit (NICU) of a tertiary hospital. Inborn babies with birth weight ≤1700 g and gestational age ≤37 weeks were included. Change in incidence and severity of ROP were compared to a similar study in the same NICU between January and December 1993.

Results: The 2013 study included higher numbers of newborn infants than the 1993 study (293 vs. 157). The mean (SD) birth weight and gestational age of the infants in the 2013 study were significantly lower than the 1993 study [1288.6 (229.8) vs. 1378.1 (232.6) g); p = 0.0001 and 31.7 (2.1) vs. 32.2 (2.31) weeks; p = 0.04]. Nevertheless, the overall incidence of ROP decreased from 49% to 26.6% (p < 0.001) after the 20-year interval. The incidence of stage 3 ROP decreased non-significantly from 24.7% to 12.8% (p = 0.058). Multivariate logistic regression analysis showed that birth weight ≤1250 g and belonging to the 1993 cohort were independently associated with an increased risk of ROP after adjusting for covariates (p = 0.013).

Conclusion: The incidence of ROP improved significantly over a 20-year period in association with improved NICU management strategies despite an increase in the number of eligible neonates with lower birth weights and gestational ages.

Keywords: NICU; ROP; Retinopathy of prematurity; incidence; preterm; screening.