Retinopathy of prematurity: A study of prevalence and risk factors

Abstract

Background:Retinopathy of prematurity (ROP) is a serious complication of prematurity treatment and can lead to blindness unless recognized and treated early.Objective:The objective was to estimate the prevalence of ROP in preterm infants in the Neonatal Intensive Care Unit (NICU), to identify the risk factors which predispose to ROP, and to assess the outcome of these cases.Materials and Methods:A ROP prospective screening survey was performed enrolling all prematures admitted to the NICU from January 2009 to December 2010, with a gestational age of 32 weeks or less at birth and a birth weight of 1500 g or less. Infants whose gestational age was >32 weeks or birth weight was >1500 g were included if they were exposed to oxygen therapy for more than 7 days. A total of 172 infants (84 males and 88 females) had retinal evaluation by indirect ophthalmoscopy from the fourth postnatal week and followed up periodically. Perinatal risk factors for ROP were assessed using univariate and multivariate analysis. Infants who progressed to stage 3 ROP were given laser therapy.Results:Out of the studied 172 infants, 33 infants (19.2%) developed ROP in one or both eyes; 18 (54.5%) cases stage 1, 9 (27.3%) cases stage 2, and 6 (18.2%) cases stage 3. None of the studied neonates presented ROP at stages 4 or 5. The six cases diagnosed as ROP stage 3 underwent laser ablative therapy. Univariate analysis showed that there was a significant relationship between the occurrence of ROP and gestational age (P = 0.000), sepsis (P = 0.004), oxygen therapy (P = 0.018), and frequency of blood transfusions (P = 0.030). However, an insignificant relationship was found between the occurrence of ROP and sex, mode of delivery, birth weight, respiratory distress syndrome, patent ductus arteriosus, intraventricular hemorrhage, hypotension, phototherapy, duration of oxygen therapy, mechanical ventilation, and CPAP (all P > 0.05). Gestational age, sepsis, oxygen therapy, and frequency of blood transfusions remained significant variables after logistic regression analysis.Conclusion:The prevalence of ROP in this study was 19.2%; low gestational age, sepsis, oxygen therapy, and frequent blood transfusions were significant risk factors for ROP. Laser was effective in treatment and decreasing the progression of ROP. As this is a unit-based study, a comprehensive countrywide survey on ROP in Egypt is recommended to determine any regional differences in disease prevalence.

A prospective study to determine the incidence of retinopathy of prematurity at a tertiary care centre in Western Rajasthan and delineate its risk factors

“…Similarly, in the study done at Egypt, 22 (26.5%) out of 83 pre-terms with O2 therapy developed ROP while only 11 (12.35%) out of the other 89 preterms who were not exposed to O2 developed ROP suggesting it to have a significant association (p=0.018) with the relative risk (RR) of 2.14 (1.10-4.14) and in the study done at Bangalore, O2 therapy for >3days and ROP had a significant association (p=0.01) with the relative risk (RR) of 1.57 (1.15-2.13). 15,6 Similar significant association with O2 therapy was also seen in the studies by Gupta VP et al (p=0.01) and Chaudhari S. et al (p=0.03). 5,4 However, no significant association with O2 therapy was seen in the study done by Samatha P et al (p=0.09).…”

“…All were having no significant association with ROP. [11][12][13][14][15][16]8 Significantly lower incidence may explained by the fact that these studies involved extremely premature infants also and very low birth weight infants and loss of such infants due to death or lost to follow-up in our study.…”

“…11 Similar significant association with low birth weight was also seen in the studies by Gupta VP et al (p=0.02), Rao KA et al (p=0.01), Shah VA et al and Chen Y et al 5,13,14,17 However, no significant association with low birth weight was seen in the study done by Swarna R et al (p=0.09) and Hakeem AH et al (p=0.10). 6,15 Sepsis was found to be significant factor for ROP like in a study at Egypt, 29 (25.21%) out of the 115 septic preterms were found to have ROP while only 4 (7.01%) out of the other 57 pre-terms developed ROP suggesting sepsis to have a significant association with ROP (p=0.004) with the RR of 3.59 (1.32-9.72).…”

“…Also, in a study on 172 pre-terms at Egypt, 33 had ROP, out of which 45.83% (n=11) of <32 wks and only 14.86% (n=22) of ≥32 wks pre-terms developed ROP with a p <0.001 suggesting it to be a significant factor. 11,15 This can be explained by immaturity of vascularization that induces an increased susceptibility of the retina to oxidative damage.…”

Retinopathy of prematurity in a cohort of neonates at Groote Schuur Hospital, Cape Town, South Africa

“…[2,6,7,10,15,16] On multivariate analysis, only GA was independently associated with ROP; however, GA assessment may be inaccurate as it was based on antenatal ultrasound scans, which often occurred only after 20 weeks' gestation, and/or the Ballard score, which is only accurate to ±2 weeks. When GA is removed from the analysis, lower BW remains an independent risk factor for ROP.…”