Retinopathy prematurity: a systematic review and meta-analysis study based on neonatal and maternal risk factors

Bilirubinemia and retinopathy of prematurity in infants ≤ 29 weeks' gestational age

BACKGROUND

Bilirubin is a known antioxidant. We hypothesized that the degree of bilirubinemia is inversely associated with oxidative stress-mediated retinopathy of prematurity (ROP).

METHODS

A prospective study was performed to determine if bilirubinemia is associated with ROP in infants ≤ 29 wks' gestational age and birth weights ≤ 1000 g. Total serum bilirubin (TSB) levels were measured at least twice daily during the first week and at least daily during the second week to determine peak and mean TSB levels. The outcomes were the incidence and severity of ROP.

RESULTS

Of 193 infants studied, 110 developed ROP: 53 had mild (stage 1 in zone 2 or 3); 31 had moderate (stage 2 in zone 2 or 3); and 26 had severe ROP ( ≥ stage 3 in any zone or any stage in zone 1). Mean TSB levels were associated with the severity (adjusted odds ratio [AOR] 0.68, 95% confidence interval [CI]:0.47-0.98, p = 0.04), but not with the incidence of ROP (AOR 0.81, 95% CI:0.52-1.27, p = 0.3). Peak TSB levels were also associated with the severity (AOR 0.71, 95% CI:0.52-0.96, p = 0.02), but not with the incidence of ROP (AOR 0.71, 95% CI:0.48-1.01, p = 0.07).

CONCLUSIONS

Bilirubinemia may be protective against severity of ROP.

IMPACT

Retinopathy of prematurity (ROP) is a disease mediated by oxidative stress. Increasing antioxidant status may decrease the incidence and severity of ROP. Bilirubin is a known antioxidant; however, findings from observational studies evaluating the role of bilirubinemia against the incidence and/or severity of ROP in premature infants are conflicting. Our findings from this prospective study suggests that bilirubinemia may be protective against the severity of ROP.

Neonatal Sepsis Episodes and Retinopathy of Prematurity in Very Preterm Infants

Importance

Retinopathy of prematurity (ROP) is a major morbidity of preterm infants causing visual impairment, including blindness, for which timely treatment is vital and prevention is key. Increasing evidence suggests that exposure to neonatal sepsis contributes to ROP development.

Objective

To investigate the association between neonatal sepsis and ROP in 2 large-scale cohorts of preterm infants born at less than 29 weeks' gestation.

Design, Setting, and Participants

This retrospective cohort study was conducted using data from the German Neonatal Network (GNN) and Norwegian Neonatal Network (NNN). The GNN involves 68 and the NNN includes 21 level III neonatal intensive care units. Participants were infants born at a gestation of 22 weeks and 0 days to 28 weeks and 6 days and enrolled in the GNN between January 1, 2009, and December 31, 2022, and NNN between January 1, 2009, and December 31, 2018. Data were analyzed from February through September 2023.

Exposure

Single or multiple episodes of culture-proven sepsis.

Main Outcomes and Measures

Any ROP and treatment-warranted ROP.

Results

Among 12 794 infants in the GNN (6043 female [47.2%] and 6751 male [52.8%]; mean [SD] gestational age, 26.4 [1.5] weeks) and 1844 infants in the NNN (866 female [47.0%] and 978 male [53.0%]; mean [SD] gestational age, 25.6 [1.5] weeks), the mean (SD) birth weight was 848 (229) g and 807 (215) g, respectively. Any ROP was present in 6370 infants (49.8%) in GNN and 620 infants (33.6%) in NNN, and treatment-warranted ROP was present in 840 infants (6.6%) in GNN and 140 infants (7.6%) in NNN. In both cohorts, there were increasing rates of treatment-warranted ROP with each sepsis episode (no sepsis: 572 of 10 658 infants [5.4%] in GNN and 85 of 1492 infants (5.7%) in NNN; 1 episode: 190 of 1738 infants in GNN [10.9%] and 29 of 293 infants [9.9%] in NNN; 2 episodes: 53 of 314 infants in GNN [16.9%] and 13 of 49 infants [26.5%] in NNN; 3 episodes: 25 of 84 infants [29.8%] in GNN and 3 of 10 infants [30.0%] in NNN). After adjusting for multiple confounders in the GNN dataset, the number of sepsis episodes was associated with ROP and treatment-warranted ROP compared with 0 episodes (1 episode: adjusted odds ratio [aOR], 1.44 [95% CI, 1.27-1.63]; P < .001 and OR, 1.60 [95% CI, 1.31-1.96]; P < .001, respectively; 2 episodes: OR, 1.81 [95% CI, 1.35-2.42]; P < .001 and OR, 2.38 [95% CI, 1.68-3.37]; P < .001, respectively; 3 episodes: OR, 4.39 [95% CI, 2.19-8.78]; P < .001 and OR, 3.88 [95% CI, 2.29-6.55]; P < .001, respectively). These associations were confirmed for any ROP by propensity score matching (for example, the aOR with propensity score matching was 1.76 [95% CI, 1.54-2.02]; P < .001 for 1 episode vs 0 episodes and 1.58 [95% CI, 1.12-2.22]; P = .007 for 3 episodes vs 0 or 1 episode). In the NNN dataset, surgical NEC was associated with treatment-warranted ROP (multivariable analysis: aOR, 3.37 [95% CI, 1.78-6.37]; P < .001).

Conclusions and Relevance

This study found that in the large-scale GNN cohort, recurrent culture-proven sepsis was associated with ROP and treatment-warranted ROP in infants born at less than 29 weeks.

Risk factor-based models to predict severe retinopathy of prematurity in preterm Thai infants

PURPOSE

To develop prediction models for severe retinopathy of prematurity (ROP) based on risk factors in preterm Thai infants to reduce unnecessary eye examinations in low-risk infants.

METHODS

This retrospective cohort study included preterm infants screened for ROP in a tertiary hospital in Bangkok, Thailand, between September 2009 and December 2020. A predictive score model and a risk factor-based algorithm were developed based on the risk factors identified by a multivariate logistic regression analysis. Validity scores, and corresponding 95% confidence intervals (CIs), were reported.

RESULTS

The mean gestational age and birth weight (standard deviation) of 845 enrolled infants were 30.3 (2.6) weeks and 1264.9 (398.1) g, respectively. The prevalence of ROP was 26.2%. Independent risk factors across models included gestational age, birth weight, no antenatal steroid use, postnatal steroid use, duration of oxygen supplementation, and weight gain during the first 4 weeks of life. The predictive score had a sensitivity (95% CI) of 92.2% (83.0, 96.6), negative predictive value (NPV) of 99.2% (98.1, 99.6), and negative likelihood ratio (NLR) of 0.1. The risk factor-based algorithm revealed a sensitivity of 100% (94, 100), NPV of 100% (99, 100), and NLR of 0. Similar validity was observed when "any oxygen supplementation" replaced "duration of oxygen supplementation." Predictive score, unmodified, and modified algorithms reduced eye examinations by 71%, 43%, and 16%, respectively.

CONCLUSIONS

Our risk factor-based algorithm offered an efficient approach to reducing unnecessary eye examinations while maintaining the safety of infants at risk of severe ROP. Prospective validation of the model is required.

Histological Chorioamnionitis and Funisitis as New Risk Factors for Retinopathy of Prematurity: A Meta-analysis

OBJECTIVE

 The role of placental inflammation in neonatal morbidities is underestimated due to lack of placental examination. This meta-analysis aims to assess the association between histological chorioamnionitis (HCA) with and without funisitis (FUN) and risk of retinopathy of prematurity (ROP).

STUDY DESIGN

 Forty-five studies reporting (unadjusted) data on HCA without FUN and HCA with FUN in neonates with ROP were included. Primary outcomes were any stage ROP and severe ROP. Potential confounders explored were gestational age (GA) at birth, birthweight, maternal steroid use, necrotizing enterocolitis, sepsis (suspected/proven) and mechanical ventilation duration.

RESULTS

 Neonates with HCA had increased risk for any stage ROP (odds ratio [OR] 1.8; 95% confidence interval [CI] 1.3-2.4) and severe ROP (OR 1.5; 95% CI 1.2-1.8) compared with neonates without HCA. The rates of any stage ROP (OR 1.8; 95% CI 1.4-2.2) and severe ROP (OR 1.4; 95% CI 1.1-1.6) were higher in neonates with FUN compared with neonates without FUN. Multivariate meta-regression analysis suggests that lower GA increases the effect size between FUN and severe ROP.

CONCLUSION

 This meta-analysis confirms that presence of HCA and FUN are risk factors for any stage ROP and severe ROP. Structured histological placental examination of HCA and FUN may be a tool to further refine the ROP risk profile.

KEY POINTS

· This systematic review confirms that HCA is a risk factor for ROP.. · This meta-analysis reveals that FUN results in an even higher risk for developing ROP.. · Placental examination of HCA/FUN may be a tool to further refine the ROP risk profile..

Sex differences in the risk of retinopathy of prematurity: a systematic review, frequentist and Bayesian meta-analysis, and meta-regression

BACKGROUND

Retinopathy of prematurity (ROP) is generally considered to be more frequent in males than in females. However, it is not known whether sex differences in ROP affect all degrees of the condition, are global and have changed as neonatology has developed. We aimed to conduct a systematic review and meta-analysis of studies addressing sex differences in the risk of developing ROP.

METHODS

PubMed/MEDLINE and Embase databases were searched. The frequentist, random-effects risk ratio (RR) and 95% confidence interval (CI) were calculated. Bayesian model averaged (BMA) meta-analysis was used to calculate the Bayes factors (BFs). The BF10 is the ratio of the probability of the data under the alternative hypothesis (H1) over the probability of the data under the null hypothesis (H0).

RESULTS

We included 205 studies (867,252 infants). Frequentist meta-analysis showed a positive association between male sex and severe ROP (113 studies, RR = 1.14, 95% CI = 1.07-1.22) but no association with any ROP (144 studies, RR = 1.00, 95% CI = 0.96-1.03). BMA showed extreme evidence in favor of H1 for severe ROP (BF10 = 71,174) and strong evidence in favor of H0 for any ROP (BF10 = 0.05). The association between male sex and severe ROP remained stable over time and was present only in cohorts from countries with a high or high-middle sociodemographic index.

CONCLUSIONS

Our study confirms the presence of a male disadvantage in severe ROP but not in less severe forms of the disease. There are variations in the sex differences in ROP, depending on geographical location and sociodemographic level of the countries.

Effects of size at birth on health, growth and developmental outcomes in children up to age 18: an umbrella review

BACKGROUND

Size at birth, an indicator of intrauterine growth, has been studied extensively in relation to subsequent health, growth and developmental outcomes. Our umbrella review synthesises evidence from systematic reviews and meta-analyses on the effects of size at birth on subsequent health, growth and development in children and adolescents up to age 18, and identifies gaps.

METHODS

We searched five databases from inception to mid-July 2021 to identify eligible systematic reviews and meta-analyses. For each meta-analysis, we extracted data on the exposures and outcomes measured and the strength of the association.

FINDINGS

We screened 16 641 articles and identified 302 systematic reviews. The literature operationalised size at birth (birth weight and/or gestation) in 12 ways. There were 1041 meta-analyses of associations between size at birth and 67 outcomes. Thirteen outcomes had no meta-analysis.Small size at birth was examined for 50 outcomes and was associated with over half of these (32 of 50); continuous/post-term/large size at birth was examined for 35 outcomes and was consistently associated with 11 of the 35 outcomes. Seventy-three meta-analyses (in 11 reviews) compared risks by size for gestational age (GA), stratified by preterm and term. Prematurity mechanisms were the key aetiologies linked to mortality and cognitive development, while intrauterine growth restriction (IUGR), manifesting as small for GA, was primarily linked to underweight and stunting.

INTERPRETATION

Future reviews should use methodologically sound comparators to further understand aetiological mechanisms linking IUGR and prematurity to subsequent outcomes. Future research should focus on understudied exposures (large size at birth and size at birth stratified by gestation), gaps in outcomes (specifically those without reviews or meta-analysis and stratified by age group of children) and neglected populations.

PROSPERO REGISTRATION NUMBER

CRD42021268843.

A Prospective Analysis of the Retinopathy of Prematurity Correlated with the Inflammatory Status of the Extremely Premature and Very Premature Neonates

Retinopathy of Prematurity (ROP) is a major cause of blindness in premature infants. This study aimed to evaluate the association between inflammatory markers and ROP development in extremely premature and very premature neonates and identify potential inflammatory biomarkers for ROP risk prediction. This prospective study was conducted from January 2021 to January 2023 in two clinical hospitals associated with the "Victor Babes" University of Medicine and Pharmacy Timisoara. The study population comprised neonates with a gestational age of less than 32 weeks. Various inflammatory markers, including total white blood cell count, polymorphonuclear leukocytes, C-reactive protein, interleukin-6, and lactate dehydrogenase, were analyzed from blood samples collected at birth and three days postnatally. ROP was diagnosed and classified following the International Classification of Retinopathy of Prematurity. The study included 48 neonates, 12 Extremely Premature Infants (EPI), and 36 Very Premature Infants (VPI). The EPI group had significantly higher mean interleukin-6 and lactate dehydrogenase levels at birth and three days postnatally than the VPI group. C-reactive protein levels at three days were significantly higher in the VPI group. Umbilical cord inflammation and ROP severity were found to have a statistically significant positive correlation. Half of the EPIs had moderate to severe ROP, significantly more than in the VPI group. The duration of oxygen supplementation, mechanical ventilation, Continuous Positive Airway Pressure (CPAP), gestational age less than 28 weeks, and umbilical cord inflammation at or above stage 3 were significant risk factors for developing ROP stage 2 or above. Elevated CRP and IL-6 were also significantly associated with an increased risk of developing ROP stage 2 or above, highlighting their potential as biomarkers for ROP risk prediction. This study suggests a significant association between inflammatory markers and ROP development in extremely premature and very premature neonates. These findings could contribute to the identification of potential inflammatory biomarkers for ROP risk prediction, improving early diagnosis and intervention strategies for this condition.

Retinopathy of prematurity: risk stratification by gestational age

OBJECTIVE

To identify gestational age (GA) specific risk factors for severe ROP (sROP).

STUDY DESIGN

Single-center cohort stratified by GA into <24 weeks, 24-26 weeks and ≥27 weeks.

RESULTS

132/1106 (11.9%) developed sROP. Time to full feeds was the only risk factor [HR 1.003 (1.001-1.006), p = 0.04] for infants<24 weeks GA. For infants 24-26 weeks GA, a higher GA was protective [HR 0.66 (0.51-0.85), p < 0.01], whereas steroids for bronchopulmonary dysplasia (BPD) [HR 2.21 (1.28-3.26), p < 0.01], patent ductus arteriosus (PDA) ligation [HR 1.99 (1.25-3.11), p < 0.01] and use of nitric oxide [HR 1.96 (1.11-3.30), p = 0.01] increased the hazard of sROP. Increasing birthweight was protective [HR 0.70 (0.54-0.89), p < 0.01] in infants ≥27 weeks GA. Cumulative hazard of sROP reached 1.0 by fifteen weeks for <24 weeks GA, 0.4 by twenty weeks for 24-26 weeks GA, and 0.05 by twenty weeks after birth for ≥27 weeks GA.

CONCLUSIONS

Risk factors, cumulative hazard, and time to sROP vary by GA.

Systemic Cytokines in Retinopathy of Prematurity

Retinopathy of prematurity (ROP), a vasoproliferative vitreoretinal disorder, is the leading cause of childhood blindness worldwide. Although angiogenic pathways have been the main focus, cytokine-mediated inflammation is also involved in ROP etiology. Herein, we illustrate the characteristics and actions of all cytokines involved in ROP pathogenesis. The two-phase (vaso-obliteration followed by vasoproliferation) theory outlines the evaluation of cytokines in a time-dependent manner. Levels of cytokines may even differ between the blood and the vitreous. Data from animal models of oxygen-induced retinopathy are also valuable. Although conventional cryotherapy and laser photocoagulation are well established and anti-vascular endothelial growth factor agents are available, less destructive novel therapeutics that can precisely target the signaling pathways are required. Linking the cytokines involved in ROP to other maternal and neonatal diseases and conditions provides insights into the management of ROP. Suppressing disordered retinal angiogenesis via the modulation of hypoxia-inducible factor, supplementation of insulin-like growth factor (IGF)-1/IGF-binding protein 3 complex, erythropoietin, and its derivatives, polyunsaturated fatty acids, and inhibition of secretogranin III have attracted the attention of researchers. Recently, gut microbiota modulation, non-coding RNAs, and gene therapies have shown promise in regulating ROP. These emerging therapeutics can be used to treat preterm infants with ROP.

[Influence of hypotension on the short-term prognosis of preterm infants with a gestational age of <32 weeks]

OBJECTIVES

To investigate the influence of early-stage hypotension defined as mean arterial pressure (MAP)<gestational age (weeks) or MAP<30 mmHg on the short-term prognosis of preterm infants with a gestational age of <32 weeks.

METHODS

A total of 320 preterm infants who were admitted to Maternal and Child Health Hospital of Hubei Province, Tongji Medical College, Huazhong University of Science and Technology from April 2020 to August 2021 and met the inclusion criteria were enrolled in this prospective study. Blood pressure within 72 hours was monitored. The definition of hypotension and grouping were as follows: (1) Of the 320 preterm infants, those with MAP<gestational age in 2 consecutive measurements served as the hypotension group (n=104), and the others (n=216) served as the control group; (2) Of the 320 preterm infants, those with MAP<30 mmHg in 2 consecutive measurements served as the hypotension group (n=114), and the others served as the control group (n=206). Perinatal data and clinical data during hospitalization were collected.Poor short-term prognosis was defined as death during hospitalization and/or grade Ⅲ-Ⅳ periventricular-intraventricular hemorrhage identified within 1 week after birth. The multivariate logistic regression analysis was used to investigate the influence of hypotension based on the above two definitions on the short-term prognosis of preterm infants.

RESULTS

Compared with the control group, the hypotension group based on the above two definitions had higher incidence rates of the clinical manifestations of hypoperfusion, poor prognosis, hemodynamically significant patent ductus arteriosus, and pulmonary hemorrhage (P<0.05). In addition, compared with the control group, the hypotension group defined by MAP<30 mmHg had higher incidence rates of periventricular-intraventricular hemorrhage and bronchopulmonary dysplasia and mortality rate during hospitalization (P<0.05). The incidence of poor short-term prognosis in the hypotension group defined by MAP<30 mmHg was higher than that in the hypotension group defined by MAP<gestational age (18.4% vs 12.5%), but the difference was not statistically significant (P>0.05).The univariate analysis showed that the poor short-term prognosis was related to birth of cesarean section, gestational age, an Apgar score of ≤ 5 at 5 minutes, use of vasoactive drugs within 72 hours, mechanical ventilation within 72 hours, and hypotension under the two definitions (P<0.05).The multivariate logistic regression showed that hypotension based on either definition was not an independent risk factor for poor prognosis (P>0.05).

CONCLUSIONS

Hypotension based on either definition is not an independent risk factor for short-term poor prognosis in preterm infants with a gestational age of <32 weeks. Hypotension defined by MAP<30 mmHg might be more sensitive than that defined by MAP<gestational age in predicting short-term adverse outcomes, which needs further analysis by large sample studies.