Prevalence and risk factors of retinopathy of prematurity in Iran: a systematic review and meta-analysis

Background: Retinopathy of prematurity (ROP) refers to the developmental disorder of the retina in premature infants and is one of the most serious and most dangerous complications in premature infants. The prevalence of ROP in Iran is different in various parts of Iran and its prevalence is reported to be 1-70% in different regions. This study aims to determine the prevalence and risk factors of ROP in Iran.

Methods: This review article was conducted based on the preferred reporting items for systematic review and meta-analysis (PRISMA) protocols. To find literature about ROP in Iran, a comprehensive search was done using MeSH keywords in several online databases such as PubMed, Ovid, Science Direct, EMBASE, Web of Science, CINAHL, EBSCO, Magiran, Iranmedex, SID, Medlib, IranDoc, as well as the Google Scholar search engine until May 2017. Comprehensive Meta-analysis Software (CMA) Version 2 was used for data analysis.

Results: According to 42 studies including 18,000 premature infants, the prevalence of ROP was reported to be 23.5% (95% CI: 20.4-26.8) in Iran. The prevalence of ROP stages 1, 2, 3, 4 and 5 was 7.9% (95% CI: 5.3-11.5), 9.7% (95% CI: 6.1-15.3), 2.8% (95% CI: 1.6-4.9), 2.9% (95% CI: 1.9-4.5) and 3.6% (95% CI: 2.4-5.2), respectively. The prevalence of ROP in Iranian girls and boys premature infants was 18.3% (95% CI: 12.8-25.4) and 18.9% (95% CI: 11.9-28.5), respectively. The lowest prevalence of ROP was in the West of Iran (12.3% [95% CI: 7.6-19.1]), while the highest prevalence was associated with the Center of Iran (24.9% [95% CI: 21.8-28.4]). The prevalence of ROP is increasing according to the year of study, and this relationship is not significant (p = 0.181). The significant risk factors for ROP were small gestational age (p < 0.001), low birth weight (p < 0.001), septicemia (p = 0.021), respiratory distress syndrome (p = 0.036), intraventricular hemorrhage (p = 0.005), continuous positive pressure ventilation (p = 0.023), saturation above 50% (p = 0.023), apnea (p = 0.002), frequency and duration of blood transfusion, oxygen therapy and phototherapy (p < 0.05), whereas pre-eclampsia decreased the prevalence of ROP (p = 0.014).

Conclusion: Considering the high prevalence of ROP in Iran, screening and close supervision by experienced ophthalmologists to diagnose and treat the common complications of pre-maturity and prevent visual impairment or blindness is necessary.