{
  "abstract": "Objective Multiple births are common in randomised trials targeting preterm populations. Clustering due to multiple births is often overlooked in individual trials and may impact the results of meta-analyses that pool their results. We aimed to assess how multiple births have been handled in the reporting and meta-analyses of recent systematic reviews.Design We conducted a methodological systematic review of Cochrane and non-Cochrane systematic reviews. The search was conducted on 10 September 2024 in the Cochrane Database of Systematic Reviews and PubMed for articles published in the previous 12 months. Reviews were eligible if they involved randomised trials of interventions delivered in pregnancy or infancy, included multiple births and reported results of at least one aggregate data meta-analysis for an infant outcome.Results After screening 222 articles, 39 had unclear eligibility due to making no mention of multiple births and nine met the eligibility criteria (five Cochrane and four non-Cochrane reviews). Multiple births were inconsistently handled across included reviews. The degree of clustering due to multiple births was poorly described and meta-analyses accounting for clustering were rarely reported (2/9 reviews; 22%). CIs around pooled treatment effect estimates were wider after accounting for clustering.Conclusions Clustering due to multiple births is a poorly recognised issue in systematic reviews and meta-analyses. Given the potential for this clustering to alter conclusions about the effectiveness of interventions, we recommend accounting for clustering due to multiple births in future meta-analyses.",
  "authors": [
    {
      "affiliations": [
        "Women and Kids Theme, South Australian Health and Medical Research Institute Limited, Adelaide, South Australia, Australia",
        "School of Public Health, Adelaide University, Adelaide, South Australia, Australia"
      ],
      "name": "Lisa N Yelland"
    },
    {
      "affiliations": [
        "NHMRC Clinical Trials Centre, The University of Sydney, Sydney, New South Wales, Australia"
      ],
      "name": "Kristy P Robledo"
    },
    {
      "affiliations": [
        "Women and Kids Theme, South Australian Health and Medical Research Institute Limited, Adelaide, South Australia, Australia",
        "School of Medicine, Adelaide University, Adelaide, South Australia, Australia"
      ],
      "name": "Kylie M Lange"
    },
    {
      "affiliations": [
        "Women and Kids Theme, South Australian Health and Medical Research Institute Limited, Adelaide, South Australia, Australia",
        "School of Public Health, Adelaide University, Adelaide, South Australia, Australia"
      ],
      "name": "Thomas R Sullivan"
    },
    {
      "affiliations": [
        "NHMRC Clinical Trials Centre, The University of Sydney, Sydney, New South Wales, Australia"
      ],
      "name": "Sol Libesman"
    },
    {
      "affiliations": [
        "Women and Kids Theme, South Australian Health and Medical Research Institute Limited, Adelaide, South Australia, Australia",
        "School of Medicine, Adelaide University, Adelaide, South Australia, Australia"
      ],
      "name": "Emily Shepherd"
    }
  ],
  "title": "Accounting for multiple births in systematic reviews of randomised trials: a methodological systematic review",
  "uid": "5896a71d-47a8-518d-840a-905190101765"
}