[Epidemiology of retinopathy of prematurity in public services from Argentina during 2008]

Incidence and risk factors of retinopathy of prematurity and utility of the national screening criteria in a tertiary center in Iran

AIM

To determine the incidence and risk factors of retinopathy of prematurity (ROP) and the sensitivity of current screening criteria in a tertiary eye center in Tehran, Iran.

METHODS

In a cross-sectional observational study, neonates weighing ≤2000 grams at birth or born <34wk gestational age (GA) and all other infants at risk of ROP admitted to the neonatal intensive care unit (NICU) or referred to our ROP clinic were investigated. The incidence of ROP and severe ROP (i.e. patients needing treatment) were determined. The associations between risk factors and the development and severity of ROP were assessed. We also examined the sensitivity of the current national screening guideline in Iran.

RESULTS

Among 207 infants, the incidence of ROP and severe ROP was 33.3% and 11.1%, respectively. Mean GA and birth weight (BW) were significantly lower in ROP vs non-ROP infants (29±2wk vs 33±3wk, P<0.001; 1274±489 g vs 1916±550 g, P<0.001, respectively). Univariate analysis displayed significant association between ROP incidence and GA, BW, NICU admission period, blood transfusion, surfactant usage, sepsis, intraventricular hemorrhage and patent ductus arteriosus (P<0.05 for all). BW [relative risk (RR): 0.857 (0.711-0.873), P<0.001], GA [RR: 0.788 (0.711-0.873), P<0.001] and blood transfusion [RR: 1.888 (0.995-3.583), P=0.052] were independent ROP risk factors. The sensitivity of country-specific screening guidelines was 95.7% and 100% for overall and severe ROP detection, respectively.

CONCLUSION

ROP incidence is relatively high in Iran. Identifying ROP risk factors results in more accurate screening and reduces the risk of irreversible vision loss. The ROP screening criteria utilized in Iran are efficient at the present time.

Incidence and risk factors for retinopathy of prematurity: a retrospective cohort study

BACKGROUND AND OBJECTIVES

Advances in neonatal care promoted increased survival rates of preterm infants, with a consequent increase in the number of children affected by retinopathy of prematurity (ROP). This study estimates the incidence of ROP and evaluates potential risk factors associated.

METHODS

A retrospective cohort study of preterm infants born in a tertiary neonatal intensive care unit was conducted from March 2005 to August 2015. Six hundred and thirty-nine newborns were included based on the following criteria: infants born with less than 32 weeks' gestation or birth weight below 1500 g; or neonates born with 32-37 weeks' gestation or birth weight above 1500 g and any of the following associated: multiple gestation, respiratory distress syndrome, sepsis, blood transfusions or intraventricular hemorrhage. Neonates were followed up until disease resolution or until treatment criteria was achieved.

RESULTS

A total of 602 newborns were evaluated after applying the exclusion criteria. Mean gestational age was 30.7 ± 2.5 weeks. The incidences of ROP at any stage and of type 1 prethreshold ROP were 33.9 and 5.0% respectively. Logistic regression analysis revealed that risk factors associated with ROP at any stage were extremely low birth weight (ELBW) (odds ratio [OR] = 3.10; 95% confidence interval [95% CI]:1.73-5.55), pulmonary diseases (OR = 2.49; 95% CI: 1.35-4.59), intraventricular hemorrhage (OR = 2.17; 95% CI: 1.10-4.30), and low gestational age (OR = 0.81; 95% CI: 0.73-0.91). The main risk factors associated with type 1 prethreshold ROP were pulmonary diseases (OR = 9.58; 95% CI: 1.27-72.04) and ELBW (OR = 3.66; 95% CI: 1.67-8.00).

CONCLUSION

This study found a significant incidence of ROP (33.9%) in the studied population, and highlighted pulmonary diseases as a significant risk factor for type 1 prethreshold ROP.

Effects of aminoguanidine on retinal apoptosis in mice with oxygen-induced retinopathy

AIM

To explore the protective effects of aminoguanidine (AG) on retinal apoptosis in mice with oxygen-induced retinopathy (OIR).

METHODS

A total of 80 C57BL/6J mice, aged 7 days, were randomly divided into four groups: normal, high oxygen, high oxygen saline and high oxygen treated with AG. In the normal group, mice were housed in normoxic conditions from postnatal day P7 to P17. Mice in the other 3 groups were placed under hyperoxic conditions (75±2%O2) in an oxygen-regulated chamber for 5 days and subsequently placed in normoxic conditions for 5 days. Mice in the AG group were treated once daily, from P12 to P17, with AG hemisulfate (100mg/kg body weight, intraperitoneally) dissolved in physiological saline. An equivalent amount of 0.9% physiological saline was administered, as above, to mice in the high oxygen saline group. Ten mice were randomly selected from each group on P14 and on P17, euthanized and the retinas examined. Apoptotic cells in the retina were detected using the terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) method. The expression of nitric oxide synthase (iNOS) in the retina was detected by immunohistochemistry and changes in rod cells were observed using electron microscopy.

RESULTS

TUNEL-positive cells and iNOS immunoreactive neurons were present in the inner nuclear and ganglion cell retinal layers of mice in the high oxygen group. The number of TUNEL-positive cells was significantly greater in the high oxygen group compared with the normal group (t=-20.81, P 14d <0.05; t=-15.05, P 17d <0.05). However, the number of TUNEL-positive cells in the AG treatment group was significantly lower (t=-13.21, P 14d<0.05; t=-6.61, P 17d <0.05) compared with the high oxygen group. The expression of iNOS was significantly higher in the high oxygen group compared with the normal group (t=-21.95, P 14d<0.05; t=-17.30, P 17d<0.05). However, the expression of iNOS in the AG treatment group was significantly lower (t=-12.17, P 14d<0.05; t=-10.30, P 17d<0.05) compared with the high oxygen group. The outer segments of the rods were disorganized and short in the high oxygen group. Rod morphology appeared to be slightly improved in the AG group.

CONCLUSION

AG may protect retinal neurons in OIR by inhibiting apoptosis. The mechanism may be related to iNOS.

Prevalence of retinopathy of prematurity in Latin America

The purpose of this work was to review the studies published over the last 10 years concerning the prevalence of retinopathy of prematurity (ROP) in Latin American countries, to determine if there was an improvement in ROP prevalence rates in that period, and to identify the inclusion criteria for patients at risk of developing ROP in the screening programs. A total of 33 studies from ten countries published between 2000 and 2010 were reviewed. Prevalence of any ROP stage in the regions considered ranged from 6.6% to 82%; ROP severe enough to require treatment ranged from 1.2% to 23.8%. There was no routine screening for ROP, and there was a lack of services for treatment of the disease in many countries. Inclusion criteria for patients in the studies ranged between birth weight ≤1500 g and ≤2000 g and gestational age ≤32 and <37 weeks. Use of different inclusion criteria regarding birth weight and gestational age in several Latin American studies hindered comparative analysis of the published data. Highly restrictive selection criteria for ROP screening in relation to birth weight and gestational age should not be used throughout most Latin American countries because of their different social characteristics and variable neonatal care procedures. The studies included in this review failed to provide adequate information to determine if the prevalence of ROP has decreased in Latin America.