Comparing very low birth weight versus very low gestation cohort methods for outcome analysis of high risk preterm infants

Abstract

BackgroundCompared to very low gestational age (<32 weeks, VLGA) cohorts, very low birth weight (<1500 g; VLBW) cohorts are more prone to selection bias toward small-for-gestational age (SGA) infants, which may impact upon the validity of data for benchmarking purposes.MethodData from all VLGA or VLBW infants admitted in the 3 Networks between 2008 and 2011 were used. Two-thirds of each network cohort was randomly selected to develop prediction models for mortality and composite adverse outcome (CAO: mortality or cerebral injuries, chronic lung disease, severe retinopathy or necrotizing enterocolitis) and the remaining for internal validation. Areas under the ROC curves (AUC) of the models were compared.ResultsVLBW cohort (24,335 infants) had twice more SGA infants (20.4% vs. 9.3%) than the VLGA cohort (29,180 infants) and had a higher rate of CAO (36.5% vs. 32.6%). The two models had equal prediction power for mortality and CAO (AUC 0.83), and similarly for all other cross-cohort validations (AUC 0.81–0.85). Neither model performed well for the extremes of birth weight for gestation (<1500 g and ≥32 weeks, AUC 0.50–0.65; ≥1500 g and <32 weeks, AUC 0.60–0.62).ConclusionThere was no difference in prediction power for adverse outcome between cohorting VLGA or VLBW despite substantial bias in SGA population. Either cohorting practises are suitable for international benchmarking.Electronic supplementary materialThe online version of this article (doi:10.1186/s12887-017-0921-x) contains supplementary material, which is available to authorized users.

Unprecedented reduction in births of very low birthweight (VLBW) and extremely low birthweight (ELBW) infants during the COVID-19 lockdown in Ireland: a ‘natural experiment’ allowing analysis of data from the prior two decades

“…There are two established methods for cohorting high-risk infants, by birth weight or GA. 20 A birthweight-based analysis was chosen for this study, and not primarily based on very low GA (VLGA, <32 weeks). VLBW could be through pure prematurity, a combination of prematurity and growth restriction/small for GA (SGA) or much less commonly through intrauterine growth restriction (IUGR) alone.…”

“…► Reducing VLBW and ELBW rates would be the most important 'curve to bend' to reduce infant mortality globally and thus promote the achievement of sustainable development goals for children. Birthweight-based data capture and analysis There are two established methods for cohorting highrisk infants, by birth weight or GA. 20 A birthweight-based analysis was chosen for this study, and not primarily based on very low GA (VLGA, <32 weeks). VLBW could be through pure prematurity, a combination of prematurity and growth restriction/small for GA (SGA) or much less commonly through intrauterine growth restriction (IUGR) alone.…”

“…Even though there has been increasing acceptance of GA-based cohorting, 7 29 more recent neonatal network and register-based studies comparing VLBW and VLGA cohorts found no difference in the prediction power for adverse outcomes between the two groups despite the inherent SGA bias within the VLBW group. 20 Two models also showed equal power to predict mortality and utility for benchmarking. 20 The VON database and NPEC recorded 612 Irish infants in 2017 with gestation less than 29+6/7 weeks.…”

“…20 Two models also showed equal power to predict mortality and utility for benchmarking. 20 The VON database and NPEC recorded 612 Irish infants in 2017 with gestation less than 29+6/7 weeks. 21 23 Among this national cohort only 16 (2.6%) had a birth weight above 1500 g, indicative of VLBW being an acceptable proxy for significant prematurity.…”

<p>Indications and Clinical Profile of Neonatal Admissions: A Cross-Sectional Descriptive Analysis from a Single Academic Center in Jordan</p>

“…Most reports that examined neonatal outcomes following NICU admission have focused on certain subgroups like premature infants or infants with very low birth weight (VLBW, less than 1500 grams). [9][10][11] Most US hospitals are engaged in national networks, like the Vermont Oxford Network to study VLBW infants and focus on longstanding research and quality improvement projects by comparing the data from different institutions on a regular basis. 12 To better compare the outcomes at different NICU set-ups, the level of neonatal care units has been classified into 4 major levels with level-4 units offering the most specialized services including surgical interventions.…”