Extremely or very preterm children born in the antenatal corticosteroids and surfactant era show large deficits in intelligence. No improvement in cognitive outcome was observed between 1990 and 2008

Cognitive Outcomes of Children Born Extremely or Very Preterm Since the 1990s and Associated Risk Factors: A Meta-analysis and Meta-regression. E. Sabrina Twilhaar et al. JAMA Pediatr. February 19, 2018. doi:10.1001/jamapediatrics.2017.5323

Key Points

Question:  What are the cognitive outcomes of children born extremely or very preterm since 1990, and what perinatal and demographic factors predict outcome?

Findings:  This meta-analysis of 71 studies (7752 extremely or very preterm and 5155 full-term children) showed a large (0.86 standard deviation) difference in intelligence between extremely or very preterm children and controls, which was stable in children born between 1990 and 2008. Bronchopulmonary dysplasia explained 65% of the variance in intelligence across studies.

Meaning:  Despite advancing perinatal care, cognitive outcomes of children born extremely or very preterm did not improve between 1990 and 2008; preventive strategies to reduce the incidence of bronchopulmonary dysplasia may be crucial to improve outcomes after extremely or very preterm birth.


Abstract

Importance:  Despite apparent progress in perinatal care, children born extremely or very preterm (EP/VP) remain at high risk for cognitive deficits. Insight into factors contributing to cognitive outcome is key to improve outcomes after EP/VP birth.

Objective:  To examine the cognitive abilities of children of EP/VP birth (EP/VP children) and the role of perinatal and demographic risk factors.

Data Sources:  PubMed, Web of Science, and PsycINFO were searched without language restriction (last search March 2, 2017). Key search terms included preterm, low birth weight, and intelligence.

Study Selection:  Peer-reviewed studies reporting intelligence scores of EP/VP children ( < 32 weeks of gestation) and full-term controls at age 5 years or older, born in the antenatal corticosteroids and surfactant era, were included. A total of 268 studies met selection criteria, of which 71 covered unique cohorts.

Data Extraction and Synthesis:  MOOSE guidelines were followed. Data were independently extracted by 2 researchers. Standardized mean differences in intelligence per study were pooled using random-effects meta-analysis. Heterogeneity in effect size across studies was studied using multivariate, random-effects meta-regression analysis.

Main Outcomes and Measures:  Primary outcome was intelligence. Covariates included gestational age, birth weight, birth year, age at assessment, sex, race/ethnicity, socioeconomic status, small for gestational age, intraventricular hemorrhage, periventricular leukomalacia, bronchopulmonary dysplasia (BPD), necrotizing enterocolitis, sepsis, and postnatal corticosteroid use.

Results:  due to HTML formatting issues, in first comment to this post.

Conclusions and Relevance:  Extremely or very preterm children born in the antenatal corticosteroids and surfactant era show large deficits in intelligence. No improvement in cognitive outcome was observed between 1990 and 2008. These findings emphasize that improving outcomes after EP/VP birth remains a major challenge. Bronchopulmonary dysplasia was found to be a crucial factor for cognitive outcome. Lowering the high incidence of BPD may be key to improving long-term outcomes after EP/VP birth.