Sentenac Mariane, Twilhaar Sabrina, Benhammou Valérie, Morgan Andrei S, Johnson Samantha, Chaimani Anna, Zeitlin Jennifer
Centre of Research in Epidemiology and Statistic (CRESS), Inserm, INRAE, Université Paris Cité, Paris, France.
Department of Neonatal Medicine, Maternité Port-Royal, Paris, France.
Paediatr Perinat Epidemiol. 2023 Mar;37(3):254-262. doi: 10.1111/ppe.12957. Epub 2023 Feb 6.
Meta-analyses of the voluminous scientific literature on the impact of very preterm (VPT, <32 weeks' gestation) birth on cognition find a marked deficit in intelligence quotient (IQ) among children born VPT relative to term-born peers, but with unexplained between-study heterogeneity in effect size.
To conduct an umbrella review to describe the design and methodology of primary studies and to assess whether methodological heterogeneity affects the results of meta-analyses.
Primary studies from five systematic reviews with meta-analysis on VPT birth and childhood IQ.
Information on study design, sample characteristics and results was extracted from studies. Study features covered study type, sample size, follow-up rates, adjustment for social context, management of severe impairments and test type.
We used random-effects subgroup meta-analyses and meta-regressions to investigate the contribution of study features to between-study variance in standardised mean differences (SMD) in IQ between groups.
In 58 cohorts (56%), children with severe impairments were excluded, while 23 (22%) cohorts accounted for social factors. The least reported feature was the follow-up rate (missing in 38 cohorts). The largest difference in SMDs was between studies using full scale IQ tests (61 cohorts, SMD -0.89, 95% CI -0.96, -0.82) versus short-form tests (27 cohorts, SMD -0.68, 95% CI -0.79, -0.57). The proportion of between-study variance explained by the type of test was 14%; the other features explained less than 1% of the variance.
Study design and methodology varied across studies, but most of them did not affect the variance in effect size, except the type of cognitive test. Key features, such as the follow-up rate, were not consistently reported limiting the evaluation of their potential contribution. Incomplete reporting limited the evaluation of the full impact of this methodological diversity.
对大量关于极早产（孕周<32周）对认知影响的科学文献进行的荟萃分析发现，与足月儿相比，极早产出生的儿童智商存在明显缺陷，但效应大小存在无法解释的研究间异质性。
进行一项综合评价，以描述原始研究的设计和方法，并评估方法学异质性是否会影响荟萃分析的结果。
来自五项关于极早产与儿童智商的系统评价及荟萃分析的原始研究。
从研究中提取有关研究设计、样本特征和结果的信息。研究特征包括研究类型、样本量、随访率、社会背景调整、严重损伤的处理和测试类型。
我们使用随机效应亚组荟萃分析和荟萃回归来研究研究特征对组间智商标准化均数差（SMD）研究间方差的贡献。
在58个队列（56%）中，患有严重损伤的儿童被排除在外，而23个队列（22%）考虑了社会因素。报道最少的特征是随访率（38个队列缺失）。使用全量表智商测试的研究（61个队列，SMD -0.89，95%CI -0.96，-0.82）与简式测试的研究（27个队列，SMD -0.68，95%CI -0.79，-0.57）之间SMD的差异最大。测试类型解释的研究间方差比例为14%；其他特征解释的方差不到1%。
研究设计和方法在各研究中有所不同，但除认知测试类型外，大多数并未影响效应大小的方差。关键特征，如随访率，报告不一致，限制了对其潜在贡献的评估。报告不完整限制了对这种方法学多样性全面影响的评估。
