Retinopathy of prematurity: any difference in risk factors between a high and low risk population?

Global Prevalence and Severity of Retinopathy of Prematurity over the Last Four Decades (1985-2021): A Systematic Review and Meta-Analysis

BACKGROUND

Retinopathy of prematurity (ROP) is a vasoproliferative disease of the retina that occurs in premature infants. The prevalence of ROP reported so far is inconsistent.

AIM

To conduct a systematic review to describe the trend of ROP prevalence between 1985 and 2021, and to determine the influence of countries' economic conditions on ROP prevalence.

METHODS

We searched PubMed, Embase, and Google Scholar for studies published between January 1985 and December 2021 using the following MeSH terms: "retinopathy of prematurity", "ROP", "incidence", and "prevalence". Two independent reviewers examined the articles to select studies that met the selection criteria and performed data extraction and study quality assessment. For the meta-analysis, the pooled prevalence was calculated using a random-effects model and R software.

RESULTS

Of 5,250 titles and abstracts, 139 original studies met the inclusion criteria; a total of 121,618 premature infants were included in these studies. The pooled prevalence of ROP was 31.9% (95% confidence interval [CI] 29.0-34.8) and that of severe ROP was 7.5% (6.5-8.7). In general, no significant differences in prevalence were found over the four decades; however, we found a higher prevalence in premature infants ≤28 weeks of gestational age. In addition, the highest ROP prevalence was found in lower-middle-income countries with high mortality rates. In contrast, the highest severe ROP prevalence was found in high-income countries.

CONCLUSION

ROP remains a common cause of morbidity in premature infants worldwide. Therefore, it seems necessary to maintain early identification strategies for patients at higher risk, particularly in low- and middle-income countries.

Risk factors in the development of retinopathy of prematurity: A 10-year retrospective study

OBJECTIVE

To evaluate Retinopathy of Prematurity (ROP) rate and risk factors in a large cohort of preterm newborns.

METHODS

Single center retrospective study. All preterm inborn hospitalized at the Neonatal Intensive Care Unit of the Policlinico of Catania from January 1, 2009 till December 31, 2018, were included. ROP stage and location, treatments required, maternal and infant risk factors were evaluated.

RESULTS

Medical records of 898 preterms were retrospectively examined (mean gestational age 32.9 ± 2.3 weeks). Of them 149 (16.6 %) developed bilateral ROP (92 stage 1, 44 stage 2 and 13 stage 3); 66 (7.3 %) received bilateral laser treatment. Six eyes of three patients affected by zone I ROP 1, with plus persistence 15 days after an optimal laser treatment, also received intravitreal ranibizumab injection. Risk factors for ROP development were gestational age (GA) (p < 0.001), birthweight (p < 0.001), assisted ventilation duration (p < 0.001), multiple birth (p = 0.003), erythropoietin (EPO) administration (p = 0.005) and persistence of tunica vasculosa lentis. The decision-tree analysis showed gestational age as the most significant predictive factor (P < 0.001); secondary predictive factors were EPO administration (p = 0.001) in newborns 29-31 weeks GA and birthweight lower than 2090 g (p < 0.001) in 32-34 weeks GA; in this latter group patent ductus arteriosus (PDA) was a tertiary predictive factor (p = 0.043).

CONCLUSIONS

In our study ROP incidence was 16,6 %; 7.3 % of the patients required laser treatment. Besides well-known factors, such as GA and birthweight, other factors like duration of assisted ventilation, EPO, multiple births, PDA, tunica vasculosa lentis persistence should be considered to tailor ophthalmic evaluation and follow-up.

Demographic Risk Factors of Retinopathy of Prematurity: A Systematic Review of Population-Based Studies

INTRODUCTION

Current national guidelines use gestational age (GA) and birth weight (BW) as their basis for retinopathy of prematurity (ROP) screening. The strength of association of these and other demographic risk factors is inconsistent across studies. This review aims to evaluate the strength of association of documented risk factors for ROP in large sample, population-based studies.

METHODS

MEDLINE, EMBASE, and Cochrane Library were searched from January 2010 to May 2020. Original studies reporting the risk of ROP in a region and demographic risk factors were included.

RESULTS

Eighteen studies comprising 342,005 infants were included. The overall risk of ROP in preterm infants was 18.8%. For every week decrease in GA, there was a median adjusted odds ratio (aOR) of 1.4 times (range 1.2-1.9) of developing ROP. For every 100-g decrease in BW, the median aOR was 1.8 times (range 1.2-2.7). Higher risk was found in infants with neonatal sepsis and bronchopulmonary dysplasia. The risk of any, severe, and treatment-requiring ROP was highest for 23 weeks GA, which was 66.5, 40.3, and 39.4%, respectively. Regions with higher neonatal mortality rates had the highest mean GA of infants with ROP.

CONCLUSION

For every week decrease in GA and every 100-g decrease in BW, there was a median of 1.4 times and 1.8 times the odds of developing ROP, respectively. Further research is required to clarify the role of additional risk factors.

Retinopathy of prematurity: a review of risk factors and their clinical significance

Retinopathy of prematurity (ROP) is a retinal vasoproliferative disease that affects premature infants. Despite improvements in neonatal care and management guidelines, ROP remains a leading cause of childhood blindness worldwide. Current screening guidelines are primarily based on two risk factors: birth weight and gestational age; however, many investigators have suggested other risk factors, including maternal factors, prenatal and perinatal factors, demographics, medical interventions, comorbidities of prematurity, nutrition, and genetic factors. We review the existing literature addressing various possible ROP risk factors. Although there have been contradictory reports, and the risk may vary between different populations, understanding ROP risk factors is essential to develop predictive models, to gain insights into pathophysiology of retinal vascular diseases and diseases of prematurity, and to determine future directions in management of and research in ROP.

Retinopathy of Prematurity among Very-Low-Birth-Weight Infants in Korea: Incidence, Treatment, and Risk Factors

This study was conducted to describe the incidence, risk factors, and current treatment status of retinopathy of prematurity (ROP) in very-low-birth-weight (VLBW) infants registered in the Korean Neonatal Network database. Medical records of 2,009 VLBW infants born between January 2013 and June 2014 who underwent examination by an ophthalmologist were reviewed. The total incidence of ROP was 34.1%. Of the patients, 11.6% showed ROP stage ≥ 3 and 11.5% received treatment of VLBW. Among all infants who received treatment of ROP, 63.6% underwent operation only; 16.9%, anti-vascular endothelial growth factor (anti-VEGF) treatment only; and 19.5%, both operation and anti-VEGF treatment. The mean gestational age (GA) and birth weight (BW) were significantly lower and the prevalence rates of respiratory distress syndrome, patent ductus arteriosus (PDA), invasive ventilator duration, and sepsis were significantly higher in the VLBW infants with ROP than in those without ROP. In the multivariable logistic regression analysis, PDA (odd ratio [OR], 2.1; 95% confidence interval [CI], 1.11-3.79) and invasive ventilator duration (OR, 1.0; 95% CI, 1.00-1.02) were significant risk factors of ROP and ROP stage ≥ 3. In conclusion, the high incidence of ROP is associated with low GA and BW, and attempt to reduce the aforementioned risk factors could reduce the incidence of ROP stage ≥ 3 in VLBW infants.

Frizzled-4 Variations Associated with Retinopathy and Intrauterine Growth Retardation: A Potential Marker for Prematurity and Retinopathy

PURPOSE

To present the association between mutations affecting the Wnt-signaling receptor protein (FZD4), inherited vitreoretinopathies, and retinopathy of prematurity (ROP).

DESIGN

Retrospective analysis of prospective samples at a tertiary referral center.

PARTICIPANTS

Patients referred to our practice for management of a variety of pediatric vitreoretinopathies were offered participation in an ophthalmic biobank (421 participants with vitreoretinopathies were included in this study). Full-term healthy infants (n = 98) were recruited to the study as controls.

METHODS

Patients with various vitreoretinopathies were prospectively enrolled in an ophthalmic biobank, approved by the Human Investigation Committee at William Beaumont Hospital. Retrospective genetic analysis of the FZD4 gene was performed (Sanger sequencing). Participants with a diagnosis of familial exudative vitreoretinopathy (FEVR), Norrie disease, Coats' disease, bilateral persistent fetal vasculature, and ROP were reviewed for the presence of a FZD4 variant. Data retrieval included status of retinopathy (including staging when possible), gestational age (GA), birth weight (BW) (when available), and family and birth histories.

MAIN OUTCOME MEASURES

The association of FZD4 variants with the presence of vitreoretinopathy.

RESULTS

The sequence variation p.[P33S(;)P168S] is the most prevalent FZD4 variant and is statistically significant for ROP and FEVR (P = 4.6E-04 and P = 2.4E-03, respectively) compared with full-term newborns (P = 1.7E-01). In addition, infants expressing the sequence variation tended to have significantly lower BWs for respective GA (P = 0.04). This suggests that the FZD4 p.[P33S(;)P168S] variant may be a risk factor for retinopathy and restricted intrauterine growth.

CONCLUSIONS

Testing for FZD4 gene mutations is useful in patients with suspected FEVR and ROP. The relatively high prevalence of the p.[P33S(;)P168S] variant in ROP and intrauterine growth restriction suggests that it also may be a marker for increased risk of developing ROP and preterm birth.

Educational paper: Retinopathy of prematurity

Retinopathy of prematurity (ROP) is a proliferative retinal vascular disease affecting the premature infant with an incompletely vascularized retina. The spectrum of ophthalmological findings in ROP exists from minimal sequelae, which do not affect vision, to bilateral retinal detachment and total blindness. With the increased survival of very small infants, retinopathy of prematurity has become one of the leading causes of childhood blindness. Over the past two decades, major advances have been made in understanding the pathogenesis of ROP, to a large extent as a result of changes in clinical risk factors (oxygen and non-oxygen related) and characteristics observed in ROP cases. This article provides a literature review on the evolution in clinical characteristics, classification and treatment modalities and indications of ROP. Special attention is hereby paid to the neonatal factors influencing the development of ROP and to the necessity for everyone caring for premature babies to have a well-defined screening and treatment protocol for ROP. Such screening protocol needs to be based on a unit-specific ROP risk profile and, consequently, may vary between different European regions.

CONCLUSION

Retinopathy of prematurity is an important cause of ocular morbidity and blindness in children. With better understanding of the pathogenesis, screening and treatment guidelines have changed over time and are unit specific.

A new risk-based screening criterion for treatment-demanding retinopathy of prematurity in Denmark

OBJECTIVE

The aim of this study was to uncover the most effective and safe criterion to implement for retinopathy of prematurity screening in Denmark.

METHODS

This retrospective national cohort study is based on data from 3 national registers. These registers provided on infants treated for retinopathy of prematurity, infants in need of treatment but missed by the present screening program, and the candidate neonates for advanced retinopathy of prematurity development A nonlinear logistic regression model was fitted to the data, and various screening criteria were evaluated.

RESULTS

During the study period (2002-2006), 116 infants were treated for retinopathy of prematurity, no treatment-demanding retinopathy of prematurity infants were missed by the screening program, and 182 premature infants were candidates for developing treatment-demanding retinopathy of prematurity. Screening criteria combining gestational age at delivery and birth weight limits and new risk-based criteria were compared with regards to their effectiveness. The risk-based criteria were the most effective. Use of the 0.13% risk-based criterion to define the population to be screened resulted in the detection of all treated infants in the study period and 17.4% fewer infants to screen. The model predicted this criterion to result in 1 missed case of treatment-demanding retinopathy of prematurity every 11 years and 1 case of blindness every 18 years in Denmark.

CONCLUSIONS

Screening criteria based on risk estimates of developing treatment-demanding retinopathy of prematurity are the most effective for retinopathy-of-prematurity screening. The risk-based criterion of 0.13% can safely be implemented for future retinopathy-of-prematurity screening in Denmark.

The influence of gestational age on the dynamic behavior of other risk factors associated with retinopathy of prematurity (ROP)

Background

Improved survival of preterm neonates has increased the incidence of retinopathy of prematurity (ROP) in many middle-income countries.

Aim

This study aimed to verify the main risk factors for the development of ROP according to different gestational age (GA) groups.

Methods

A prospective cohort study including infants weighing ≤1,500 g or GA ≤32 weeks at birth was conducted. The main clinical outcomes were the occurrence of any stage of ROP and severe ROP. The perinatal variables considered for the study were: birth weight; GA; gender; to be small for GA (SGA); weight gain from birth to the sixth week of life; use of oxygen in mechanical ventilation or nasal CPAP; multiple gestations; therapeutic use of surfactant, indomethacin, and erythropoietin; occurrence of sepsis, meningitis, intraventricular hemorrhage, and patent ductus arteriosus; need for and volume of blood transfusion; and 10-min Apgar score. The patients were divided into three groups according to GA: (group 1) infants of GA ≤28 weeks at birth (n = 100); (group 2) infants of GA = 29–31 weeks at birth (n = 215); and (group 3) infants of GA ≥32 weeks at birth (n = 152).

Results

A total of 467 newborn infants were included. Mean BW and GA in the total cohort were 1,216.5 g (±278.3) and 30.3 weeks (±2.2), respectively. Gestational age groups were not matched for BW and SGA. Any stage of ROP occurred in 111 patients (23.8%) and 24 (5.1%) patients developed severe ROP. Only BW and volume of blood transfusion were significant factors for the occurrence of any stage of ROP in all groups. In group 1, GA, the twin situation, and use of erythropoietin were statistically significant factors. In group 2, only GA and need for blood transfusion were significant. In group 3, use of oxygen in mechanical ventilation, sepsis, and need for blood transfusion were significant for ROP onset. The logistic regression determined that patients in groups 2 and 3 were less likely to develop ROP than patients in group 1.

Conclusions

Patients in groups 1 and 2 developed ROP due to general immaturity, whereas bigger babies, of GA ≥32 weeks, developed ROP because they were “sicker” babies with more comorbidities.

Étude épidémiologique de la rétinopathie du prématuré : les facteurs de risque au CHU de Tours

BACKGROUND

A prospective analysis of the incidence of retinopathy of prematurity (ROP) by documenting clinical perinatal characteristics of affected infants, in an attempt to describe risk factors for ROP.

MATERIALS AND METHODS

Between March 2002 and April 2004, 161 infants, with a gestational age under 31 weeks and/or a birth weight under 1500 g, were screened according to CRYO-ROP guidelines, using direct ophthalmoscopy with a Layden contact lens. Risk factors for ROP were analyzed with the Student and Fischer tests.

RESULTS

ROP developed in 15% of the cases studied, with one out of five at prethreshold or threshold levels of ROP. Gestational age at birth (p<0.0001), low birth weight (p<0.0001), the length of the infant's stay in the neonatal intensive care unit (p<0.0001), the duration of mechanical ventilation (p<0.0001), the duration of oxygen provided (p<0.0001), blood transfusions (p<0.0001), hyaline membrane disease (p=0.0257), and bronchodysplasia (p=0.0012) were significant risk factors for ROP.

CONCLUSION

Despite progress in neonatal intensive care, ROP persists and can be explained by greater and greater prematurity and earlier screening. Effective screening, done between 4 and 6 weeks of life, taking risk factors into account, can improve prognosis.

Race, gender, and clinical risk index for babies (CRIB) score as predictors of severe retinopathy of prematurity

PURPOSE

To determine whether race, gender, and the Clinical Risk Index for Babies (CRIB) illness severity score are predictors of threshold or severe prethreshold retinopathy of prematurity warranting surgery (ROP warranting surgery) and whether racial and gender differences in ROP are correlated with racial and gender differences in illness severity.

METHODS

This was a retrospective analysis of premature infants 401-1250 g at birth that were admitted to the University Hospital of Cincinnati (January 1998 to May 2003). Birth weight, gestational age, multiple birth, birth in the study hospital or elsewhere, race, gender, CRIB score, and eye findings were abstracted. The outcome variable was ROP warranting surgery.

RESULTS

Of 299 patients (596 eyes) with adequate eye and CRIB data, 35 patients (11.7%) [66 eyes; 11.1%] developed ROP warranting surgery. Multiple logistic regression analysis showed that higher CRIB score (P < 0.0001; odds ratio [OR] 1.21), male gender (P < 0.005; OR: 2.68), nonblack race (P < 0.0005; OR: 4.32), lower gestational age, and multiple birth are predictive factors for ROP warranting surgery. Because birth weight and gestational age comprise 2 of the 6 components of the CRIB score, a CRIB subscore (CRIBSUB) consisting of the remaining 4 components was tested and remained a significant predictor (P < 0.00001). Birth weight was a significant predictor when CRIBSUB was in the model but not when the CRIB score was used. The CRIB score was a predictor of neonatal mortality, but race and gender did not predict the CRIB score or neonatal mortality.

CONCLUSIONS

Nonblack race, male gender, and higher CRIB illness severity scores are predictors of ROP warranting surgery. In our population, there were no racial or gender differences in neonatal mortality or CRIB scores to explain the racial and gender differences in severity of ROP.

Relationship between hyperglycemia and retinopathy of prematurity in very low birth weight infants

Retinopathy of prematurity (ROP) is a multifactorial vasoproliferative retinal disorder that increases in incidence with decreasing gestational age. Recently, an association between hyperglycemia and severe ROP was found in extremely low birth weight infants (ELBWI). The purpose of this study was to evaluate the possible relation between hyperglycemia and ROP at any stage in very low birth weight infants (VLBWI). We analyzed the data of 201 VLBWI. The incidence of ROP and hyperglycemia was detected and the chi2 test was applied to investigate the association between the two variables. The Clinical Risk Index for Babies (CRIB) score was attributed as a marker of illness severity. The incidence of ROP and hyperglycemia in VLBWI was 35.3 and 19.4%, respectively. ROP developed more frequently in hyperglycemic infants (p < 0.001). The gestational age, birth weight, and Apgar scores were significantly lower, the CRIB score was higher in ROP patients. In hyperglycemic ROP patients the CRIB score was significantly higher compared to euglycemic ROP patients (mean (SD) 8.1 (4.2) vs. 5.5 (3.3); p < 0.01). A logistic regression model revealed that gestational age (OR 0.59; 95% CI 0.46-0.76; p < 0.001) and hyperglycemia (OR 3.15; 95% CI 1.12-8.84; p < 0.05) are independent risk factors in ROP development. When ELBWI were analyzed separately, gestational age (OR 0.38; 95% CI 0.20-0.72; p < 0.01) and CRIB score (OR 1.58; 95% CI 1.02-2.45; p < 0.05) were found as significant contributors. Further studies are needed to elucidate the pathophysiological role of hyperglycemia in the development of vasoproliferative retinal disorder.