Abstract
Purpose: :
Published outcomes for laser of ETROP Type 1 infants have a success rate of 85 -90%. However, infants with extremely low birthweights (ELBW, defined as <1000g) and/or poor postnatal weight gain are vulnerable to aggressive posterior ROP (AP-ROP), with very poor outcomes.Standard screening guidelines use gestational age and weight at birth to predict risk for severe ROP. Recent studies, including the WINROP model, have shown that poor postnatal weight gain can identify children at risk for developing high-risk ROP. The WINROP model, however requires serum IGF-1 levels which can be not only costly, but also stressful to the infant, and may not be available in remote or underserved areas. The aim of this study is to analyze postnatal weight gain as a unique predictor of ROP. Babies identified at higher risk may benefit from weekly screening exams to identify and treat AP-ROP sooner. Also, inexperienced examiners will benefit from enhanced risk stratification.
Methods: :
A retrospective chart review was performed on all infants admitted to the NICU at Wilford Hall Medical Center between January 1, 2007 and December 30, 2010. Inclusion criteria were any infants screened for ROP. Primary outcomes were gestational age, birth weight, postnatal weight gain, ROP severity and treatment received for each infant. Exclusion criteria were excessive weight gain due to pathology, such as hydrocephalus, and infants born at or after 30 weeks gestational, in order to control for age between the groups.Average weekly post-natal weight gain was compared between the treated and untreated infants. Statistical analysis and regression models were used to determine the correlation between severity of ROP and postnatal weight gain. Tables including corrected gestational age, weight, weight gain and relative risk of requiring treatment were computed.
Results: :
A statistically significant difference was found between post-natal weight gain in the treated and untreated infants. For the infants requiring treatment, a minimum weekly weight gain of 70 grams per week triggered alarms for 78% by 3 weeks of life, 92% by 4 weeks and 100% by 5 weeks. The same value triggered alarms for infants not requiring treatment for 45% at 3 weeks of life, 45% at 4 weeks and 50% at 5 weeks.
Conclusions: :
With our analysis we have a model to better stratify infants into groups based on risk of developing severe ROP as determined by weekly post-natal weight gain. High risk babies, gaining less than 70 grams per week, may benefit from more frequent screening to identify and treat AP-ROP sooner. Continued research to include an increased number of infants from various institutions would better indicate whether these findings are applicable to all NICU populations.
Keywords: retinopathy of prematurity