Treatment of retinopathy of prematurity in Northern Ireland, 2000-2011: a population-based study

The incidence and risk factors of retinopathy of prematurity in South Korea: A nationwide cohort study

Retinopathy of prematurity (ROP) is a major treatable cause of childhood blindness. Thus, epidemiological investigations are necessary for detecting and preventing ROP. Determining risk factors for ROP are also essential to improve screening methods. Therefore, we aimed to investigate the incidence and risk factors of ROP in Korea. The National Health Insurance Service (NHIS) covers almost all Koreans. Furthermore, the National Health Screening Program for Infants and Children (NHSPIC) is a government-run, health-screening program for children aged < 6 years. We used the NHIS-Infants and Children's Health Screening cohort database to evaluate the incidence of preterm infants and ROP. The database contains data on 84,005 participants, drawn from 5% of the NHSPIC survey on participants born annually during 2008 to 2012. Sociodemographic factors and systemic diseases were assessed as potential risk factors for ROP. We identified 2615 premature infants (3.11%); 846 of them had ROP (cumulative incidence: 32.4%). Although preterm births increased annually in 2008 to 2012, the ROP incidence in preterm infants did not increase by the birth year. Twenty patients (2.4%) with ROP underwent laser photocoagulation or surgery. Extremely low birth weight was a high risk factor (odds ratio [OR] = 49.86, P < .001). Moreover, chorioamnionitis (OR = 2.77, P = .028), respiratory distress syndrome (OR = 4.09, P < .001), apnea (OR = 1.59, P = .008), anemia (OR = 2.41, P < .001), and intraventricular hemorrhage (OR = 2.34, P < .001) were found to be risk factors for ROP. In conclusion, the incidence of premature babies increased between 2008 and 2012. However, the overall incidence of ROP among premature infants remained unchanged by birth year. Our findings revealed the roles of birth weight, respiratory conditions, anemia, and intraventricular hemorrhage in ROP.

Appropriate dose of intravitreal ranibizumab for ROP: a retrospective study

Objective

To compare the recurrence rate of retinopathy of prematurity (ROP) after treatment with 0.3 mg vs. 0.25 mg ranibizumab.

Subjects

All patients with ROP who underwent intravitreal injection of ranibizumab in Hainan General Hospital between January 2014 and May 2020 were included in this retrospective study.

Methods

Eighty-two cases (146 eyes) who received intravitreal injection of 0.25 mg ranibizumab were included in the conventional-dose group, and 59 cases (108 eyes) who received intravitreal injection of 0.3 mg ranibizumab were included in the high-dose group. The two groups were further divided into the 25-28-week, 29-31-week, 32-34-week, and 35-36-week GA subgroups. The differences between the conventional-dose group and the high-dose group in gestational age (GA), birth weight (BW), age at initial injection (weeks), incidence of systemic diseases, the recurrence rate of ROP, and age at retinal vascularization completed (weeks) were analyzed.

Results

GA, BW, age at initial injection, and the incidence of systemic diseases were not significantly different between the conventional-dose group and the high-dose group (p > 0.05). The recurrence rates of ROP were significantly lower in the 25-28-week, 29-31-week, and 32-34-week subgroups of the high-dose group than in the same subgroups of the conventional-dose group (p < 0.05). Within the conventional-dose group, the recurrence rate of ROP was significantly lower in the 32-34-week and 35-36-week subgroups than in the 25-28-week and 29-31-week subgroups (p < 0.05). Within the high-dose group, the recurrence rate of ROP was not significantly different between the four subgroups (p > 0.05). Retinal vascularization was completed at a later age in the 32-34-week subgroup of the high-dose group than in the 32-34-week subgroup of the conventional-dose group (p < 0.05) but was not significantly different between the two groups at any other GA range (p > 0.05). No severe ocular or systemic complications occurred in any patient.

Conclusion

Treatment with 0.3 mg ranibizumab can reduce the recurrence rate of ROP without prolonging retinal vascularization or causing serious systemic complications. Therefore, this dose may be an appropriate therapeutic dose for ROP.

Trends in the incidence of retinopathy of prematurity over a 10-year period

AIM

To describe and evaluate the trends in the incidence of retinopathy of prematurity over a 10-year period in a tertiary hospital in Hong Kong.

METHODS

A retrospective review was performed on all preterm infants screened and/or treated for retinopathy of prematurity from January 2006 to December 2015 at Prince of Wales Hospital, Hong Kong. Preterm infants with incomplete records or transferred-in from other hospitals/region solely for treatment of ROP were excluded. The incidence of any ROP or Type 1 ROP was analysed with gestational age and birth weight over a 10-year period with consecutive 2-year intervals to evaluate the trends.

RESULTS

Of all 754 infants included in the study, 234 (31.0%) patients had any ROP and 34 (4.5%) infants developed Type 1 ROP. The incidence of any ROP demonstrated a statistically significant decreasing trend over the five consecutive 2-year intervals (p = 0.016), but the incidence trend of Type 1 ROP is not statistically significant. No infants weighing more than 1250 g developed Type 1 ROP.

CONCLUSION

We observed a decreasing trend in the incidence of any ROP across the 10-year period in a tertiary hospital in Hong Kong, while the incidence of Type 1 ROP remained stable at 4.5%. The factors leading to the trend were unclear. Improved prenatal care, changing proportion of cases with different birth weight and gestational age, oxygenation level practice in neonatal unit may all contribute to the decreasing trend. Revision of screening criteria may be made according to local experience to maximise cost-effectiveness.

International variations and trends in the treatment for retinopathy of prematurity

OBJECTIVE

To compare the rates of retinopathy of prematurity (ROP) and treatment of ROP by laser or intravitreal anti-vascular endothelial growth factor among preterm neonates from high-income countries participating in the International Network for Evaluating Outcomes (iNeo) of neonates.

METHODS

A retrospective cohort study was conducted on extremely preterm infants weighing <1500 g at 24⁰ to 27⁶ weeks' gestation who were admitted to neonatal units in Australia/New Zealand, Canada, Finland, Israel, Japan, Spain, Sweden, Switzerland, Tuscany (Italy) and the UK between 2007 and 2013. Pairwise comparisons of ROP treatment in survivors between countries were evaluated by Poisson and multivariable logistic regression analyses after adjustment for confounders. A composite outcome of death or ROP treatment was compared between countries using logistic regression and standardised ratios.

RESULTS

Of 48 087 infants included in the analysis, 81.8% survived to 32 weeks postmenstrual age, and 95% of survivors were screened for ROP. Rates of any ROP ranged from 25.2% to 91.0% in Switzerland and Japan, respectively, among those examined. The overall rate of those receiving treatment was 24.9%, which varied from 4.3% to 30.4%. Adjusted risk ratios for ROP treatment were lower for Switzerland in all pairwise comparisons, whereas Japan displayed significantly higher ratios. Comparisons of the composite outcome between countries revealed similar, but less marked differences.

CONCLUSIONS

Rates of any ROP and ROP treatment varied significantly between iNeo members, while an overall decline in ROP treatment was observed during the study period. It is unclear whether these variations represent differences in care practices, diagnosis and/or treatment thresholds.

Differentially expressed miRNAs in oxygen‑induced retinopathy newborn mouse models

The present study aimed to identify microRNAs (miRNAs) involved in regulating retinal neovascularization and retinopathy of prematurity (ROP). A total of 80 healthy C57BL/6 neonatal mice were randomly divided into the oxygen-induced retinopathy (OIR) group (n=40), in which 7-day-old mice were maintained in 75% oxygen conditions for 5 days, or the control group (n=40). Following collection of retinal tissue, retinal angiography and hematoxylin and eosin (H&E) staining were performed. Total RNA was also extracted from retinal tissue, and miRNA microarrays and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were performed to identify differentially expressed miRNAs in the two groups. Retinal angiography and H&E staining revealed damage to retinas in the OIR group. Compared with the control group, 67 miRNAs were differentially expressed in the OIR group, of which 34 were upregulated and 33 were downregulated. Of these differentially expressed miRNAs, 32 exhibited a fold change ≥2, of which 21 were upregulated and 11 were downregulated. The results of RT-qPCR for miR-130a-3p and miR-5107-5p were in accordance with those of the miRNA microarray. The newly identified miRNAs may be important in the development of ROP, and may provide a basis for future research into the mechanisms of ROP.