Abstract：
Review of age of onset of necrotising enterocolitis (NEC) and focal intestinal perforation (FIP) in very preterm (≤32 weeks) and/or very low birthweight (VLBW, ≤1500 g) infants.
Preregistered review undertaken according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses in July 2021 and updated October 2021.
MEDLINE/ PubMed, Embase, CINAHL and Cochrane Central Register of Controlled Trials.
Eligible studies reported age of onset of NEC and/or FIP in randomised controlled trials of >200 or observational studies of >500 infants.
Titles/abstracts were screened; eligible articles underwent data extraction. Age of onset as day of life (DOL) and/or corrected gestational age (CGA) were extracted alongside study information, such as NEC definition, included population, intervention, location and dates studied. Weighted means were used to compare onset by birth gestation, study type, NEC definition, trial intervention, location and dates studied. Comparison was done by Mann-Whitney U test or one-way analysis of variance.
Of the 747 screened studies 188 were eligible. Removal of duplicates, studies without onset data and ineligible populations left 10 RCTs and 14 observational studies contributing 51 NEC cohorts; 49 reported onset DOL and 14 CGA. 2984 cases of NEC had average DOL onset of 16.7 (15.5 in RCTs, 16.9 in observational studies), and CGA onset of 30.1 weeks. Gestation did not impact DOL onset. No other demographic feature impacted NEC onset. Few studies included data on FIP.
Average onset of NEC in exclusively very preterm/very low birthweight infants is in the third week of life and unlike in cohorts including more mature or heavier infants is not impacted by birth gestation.
Preregistered review undertaken according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses in July 2021 and updated October 2021.
MEDLINE/ PubMed, Embase, CINAHL and Cochrane Central Register of Controlled Trials.
Eligible studies reported age of onset of NEC and/or FIP in randomised controlled trials of >200 or observational studies of >500 infants.
Titles/abstracts were screened; eligible articles underwent data extraction. Age of onset as day of life (DOL) and/or corrected gestational age (CGA) were extracted alongside study information, such as NEC definition, included population, intervention, location and dates studied. Weighted means were used to compare onset by birth gestation, study type, NEC definition, trial intervention, location and dates studied. Comparison was done by Mann-Whitney U test or one-way analysis of variance.
Of the 747 screened studies 188 were eligible. Removal of duplicates, studies without onset data and ineligible populations left 10 RCTs and 14 observational studies contributing 51 NEC cohorts; 49 reported onset DOL and 14 CGA. 2984 cases of NEC had average DOL onset of 16.7 (15.5 in RCTs, 16.9 in observational studies), and CGA onset of 30.1 weeks. Gestation did not impact DOL onset. No other demographic feature impacted NEC onset. Few studies included data on FIP.
Average onset of NEC in exclusively very preterm/very low birthweight infants is in the third week of life and unlike in cohorts including more mature or heavier infants is not impacted by birth gestation.
摘要：
回顾非常早产（≤32周）和/或非常低的出生体重（VLBW，≤1500g)婴儿。
根据2021年7月系统审查和荟萃分析的首选报告项目进行的预注册审查，并于2021年10月更新。
MEDLINE/PubMed,Embase,CINAHL和Cochrane中央对照试验登记册。
符合条件的研究报告了在200例以上婴儿的随机对照试验或500例以上婴儿的观察性研究中NEC和/或FIP的发病年龄。
对标题/摘要进行了筛选；符合条件的文章进行了数据提取。与研究信息一起提取发病年龄，如生命日（DOL）和/或校正胎龄（CGA）。如NEC定义，包括人口，干预，研究的地点和日期。加权平均值用于比较出生妊娠的发病情况，研究类型,NEC定义,试验干预，研究的地点和日期。通过Mann-WhitneyU检验或单向方差分析进行比较。
在747项筛选研究中，有188项符合条件。删除重复项,没有发病数据和不合格人群的研究留下了10项RCT和14项观察性研究,贡献了51个NEC队列;49项报告了发病DOL和14项CGA.2984例NEC平均DOL发作16.7（RCT为15.5，16.9在观察性研究中)，CGA起病30.1周。妊娠不影响DOL的发作。没有其他人口统计学特征影响NEC发病。很少有研究包括FIP的数据。
完全非常早产/非常低出生体重的婴儿的NEC平均发病在生命的第三周，与包括更成熟或更重的婴儿的队列不同，NEC不受出生妊娠的影响。
根据2021年7月系统审查和荟萃分析的首选报告项目进行的预注册审查，并于2021年10月更新。
MEDLINE/PubMed,Embase,CINAHL和Cochrane中央对照试验登记册。
符合条件的研究报告了在200例以上婴儿的随机对照试验或500例以上婴儿的观察性研究中NEC和/或FIP的发病年龄。
对标题/摘要进行了筛选；符合条件的文章进行了数据提取。与研究信息一起提取发病年龄，如生命日（DOL）和/或校正胎龄（CGA）。如NEC定义，包括人口，干预，研究的地点和日期。加权平均值用于比较出生妊娠的发病情况，研究类型,NEC定义,试验干预，研究的地点和日期。通过Mann-WhitneyU检验或单向方差分析进行比较。
在747项筛选研究中，有188项符合条件。删除重复项,没有发病数据和不合格人群的研究留下了10项RCT和14项观察性研究,贡献了51个NEC队列;49项报告了发病DOL和14项CGA.2984例NEC平均DOL发作16.7（RCT为15.5，16.9在观察性研究中)，CGA起病30.1周。妊娠不影响DOL的发作。没有其他人口统计学特征影响NEC发病。很少有研究包括FIP的数据。
完全非常早产/非常低出生体重的婴儿的NEC平均发病在生命的第三周，与包括更成熟或更重的婴儿的队列不同，NEC不受出生妊娠的影响。
