Risk factors for very preterm delivery out of a level III maternity unit: The EPIPAGE-2 cohort study

Survival and neurodevelopmental impairment of outborn preterm infants at 5.5 years of age: an EPIPAGE-2 prospective, matched study using multiple imputation

OBJECTIVE

To determine whether birth outside a level-3 centre (outborn) is associated with a difference in the combined outcome of mortality or moderate-to-severe neurological impairment at 5.5 years of age compared with birth in a level-3 centre (inborn) when antenatal steroids and gestational age (GA) are accounted for.

DESIGN

Individual matched study nested within a prospective cohort. Each outborn infant was matched using GA and antenatal steroids with a maximum of four inborns. Conditional logistic regression was used to calculate ORs before being adjusted using maternal and birth characteristics. Analyses were carried out after multiple imputation for missing data.

SETTING

EPIPAGE-2 French national prospective cohort including births up to 34 weeks GA inclusive.

PATIENTS

Outborn and inborn control infants selected between 24 and 31 weeks GA were followed in the neonatal period and to 2 and 5.5 years. 3335 infants were eligible of whom all 498 outborns and 1235 inborn infants were included-equivalent to 2.5 inborns for each outborn.

MAIN OUTCOME MEASURE

Survival without moderate-to-severe neurodevelopmental impairment at 5.5 years.

RESULTS

Chorioamnionitis, pre-eclampsia, caesarian birth and small-for-dates were more frequent among inborns, and spontaneous labour and antepartum haemorrhage among outborns. There was no difference in the main outcome measure at 5.5 years of age (adjusted OR 1.09, 95% CI 0.82 to 1.44); sensitivity analyses suggested improved outcomes at lower GAs for inborns.

CONCLUSION

In this GA and steroid matched cohort, there was no difference in survival without moderate-to-severe neurodevelopmental impairment to 5.5 years of age between inborn and outborn very preterm children. This suggests steroids might be important in determining outcomes.

Measuring severe neonatal morbidity using hospital discharge data in France

BACKGROUND

Measuring infant health at birth is key for surveillance and research in obstetrics and neonatology, but there is no international consensus on morbidity indicators. The Neonatal Adverse Outcome Indicator (NAOI) is a composite indicator, developed in Australia, which measures the burden of severe neonatal morbidity using hospital discharge data.

OBJECTIVE

To evaluate the applicability of the NAOI in France for surveillance and research.

METHODS

We constituted a cohort of live births ≥24 weeks' gestational age in Metropolitan France from 2014 to 2015 using hospital discharge, insurance claims and cause of death data. Outlier hospitals were identified using funnel plots of standardised morbidity ratios (SMR), and their coding patterns were assessed. We compared the NAOI and its component codes with published Australian and English data and estimated unadjusted and adjusted risk ratios for known risk factors for neonatal morbidity.

RESULTS

We included 1,459,123 births (511 hospitals). Twenty-eight hospitals had SMR above funnel plot control limits. Newborns with NAOI morbidities in these hospitals had lower mortality and shorter stays than in other hospitals. Amongst within-limit hospitals, NAOI prevalence was 4.8%, comparable to Australia (4.6%) and England (5.4%). Most individual components had a similar prevalence, with the exception of respiratory support, intravenous fluid procedures and infection. NAOI was lowest at 39 weeks (2.2%) with higher risks for maternal age ≥40 (relative risk [RR] 1.47, 95% confidence interval [CI] 1.42, 1.51), state medical insurance (RR 1.60, 95% CI 1.52, 1.68), male sex (RR 1.21, 95% CI 1.19, 1.23) and birthweight <3^rd percentile (RR 4.60, 95% CI 4.51, 4.69).

CONCLUSIONS

The NAOI provides valuable information on population prevalence of severe neonatal morbidity and its risk factors. Whilst the prevalence was similar in high-income countries with comparable neonatal mortality levels, ensuring valid comparisons between countries and hospitals will require further work to harmonize coding procedures, especially for infection and respiratory morbidity.