Risk Factors for Retinopathy of Prematurity with Specific Emphasis on Postnatal Weight Gain: An Observational Study

Abstract

Introduction: Retinopathy Of Prematurity (ROP) is a vasoproliferative disorder that affects premature infants with multiple risk factors. Timely screening and treatment can help decrease this preventable cause of blindness. Aim: To assess the risk factors for development of ROP, and to study its association with postnatal weight gain. Materials and Methods: This was an observational study with both prospective and retrospective arms. In the retrospective component, the case files and ROP screening records of the infants were screened, in the duration of July 2019 to February 2020. The prospective data was collected from the ongoing screening sessions, during March 2020 to November 2020. The risk factors for ROP, and postnatal weight gain was observed during the ROP screening programme conducted at the intramural Neonatal Intensive Care Unit (NICU) of Sir Sayajirao Hospital, Vadodara, Gujarat, India. Infants with Birth Weight (BW) <2000 g and Gestational Age (GA) <34 weeks and those with high risk factors {prolonged oxygen exposure, mechanical ventilation, anaemia requiring blood transfusion, Intraventricular Haemorrhage (IVH), Respiratory Distress Syndrome (RDS), Bronchopulmonary Dysplasia (BPD), recurrent apnea, hypotension requiring inotropes, surgery during first week of life, sepsis and hypoglycaemia} were included in the study. Subjects were followed-up till 44 weeks Post-Menstrual Age (PMA), or till complete vascularisation of retina or regression of ROP on retinal examination whichever was earlier. Risk factors were studied using univariate analysis and multivariate regression. Weight gain was studied using independent sample t-test. Results: A total of 486 neonates were enrolled, who underwent serial ophthalmological examinations. Out of these, 375 infants (198 (52.8%) male and 177 (42.7%) females) underwent examinations until 44 weeks of PMA or till complete retinal vascularisation, or till complete regression of ROP with or without treatment. Out of these, 173 patients had no ROP, 120 patients developed ROP which got spontaneously regressed over time and 82 patients developed severe ROP which required treatment. Mean Gestational Age (GA) in the study population was 34.35 week (±2.64 wk), and mean Birth Weight (BW) was 1.67 kg (±0.45 kg). In the group of severe ROP, mean GA was 32.03 week (±1.33 wk) and mean BW was 1.33 kg (±0.35 kg); and the mean number of positive risk factors were 5.93 (±1.77). Poor postnatal weight gain was associated with more risk of severe ROP. GA <34 week (p-value <0.0001), BW <1750 g (p-value <0.0001), oxygen exposure (p-value <0.0001), IVH (p-value <0.0001), RDS (p-value=0.0111), BPD (p-value=0.0058), hypotension requiring inotropes (p-value=0.0001) and sepsis (p-value <0.0001) were significant risk factors. On multivariate logistic regression, BW <1750 g, GA <34 week, sepsis and hypotension requiring inotropes were most important risk factors for ROP, along with poor postnatal weight gain. Conclusion: Poor postnatal weight gain is associated with increased risk of severe ROP.