Retinopathy of Prematurity: Incidence and Risk Factors

Abstract

INTRODUCTION According to the WHO data, ca. 3.9 million children are diagnosed with retinopathy of prematurity (ROP) worldwide. This disease is one of the main causes of blindness in children. AIMTo evaluate the incidence of ROP in the Department of Neonatology of the Lithuanian University of Health Sciences (LUHS), to identify the most common risk factors of this disease, and to evaluate the influence of these factors on the development of ROP. METHODS This retrospective study included 753 neonates (born at ≤ 32 weeks of gestation, weight ≤ 2,000 g) who were treated during 2003-2012 at the Department of Neonatology of the LUHS. The distribution of ROP and the frequency of its surgical treatment was evaluated in the subjects studied. We evaluated the influence of sex, gestational age (GA) (the subjects were distributed into the following groups: ≤ 25 GA, 26-27 GA, 28-30 GA, and 31-32 GA) and birth weight (the subjects were distributed into the following groups: 500-999 g, 1,000-1,499 g, and > 1,500 g) on ROP, and the distribution of this condition in groups. RESULTS ROP was diagnosed in 16% (n = 120) of subjects: 15.8% males and 16.1% females. A statistically significant correlation was found between the incidence of ROP and gestational age groups: ≤ 25 GA – 48.2%, 26-27 GA – 24.5%, 28-30 GA – 11.5%, and 31-32 GA – 4.4% (p < 0.05). The highest incidence of ROP (36.3%) was found in the group of neonates with birth weight of 500-999 g, while the incidence of this condition in other groups was much lower (1,000-1,499 g – 11%, and > 1,500 g – 0.6%); however, the difference was not statistically significant (p > 0.05). A statistically significant correlation was found between the development of ROP and congenital heart defect, hypoxia, congenital/acquired infection, bronchopulmonary dysplasia, anemia, and encephalopathy (p < 0.05). Surgical treatment was applied in 3% (n = 20) of the subjects, most frequently – in the groups with birth weight of < 1,000 g (18%) and > 1,000 g (14%) (p < 0.779). CONCLUSIONS ROP statistically significantly correlated with the neonates’ gestational age: the incidence of ROP decreased with increasing gestational age. Birth weight did not have any significant influence on the development of more severe stages of ROP or the application of surgical treatment. The incidence of ROP was statistically significantly influenced by perinatal hypoxia, congenital heart defect, infection, anemia, bronchopulmonary dysplasia, and encephalopathy.