Evidence map›Paper›PMID 34191860›Full record

ArticlePloS one2021

Bias in comparisons of mortality among very preterm births: A cohort study.

Amélie Boutin, Sarka Lisonkova, Giulia M Muraca, Neda Razaz, Shiliang Liu, Michael S Kramer, K S Joseph

Abstract readComparative Study
PubMed Full text at PMC Publisher
In one paragraph

Article in PloS one, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.

0numbers the graph read from it
0cells of the map it votes in
6citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

6 citing papers in PubMed.

  1. Article
  2. Review
  3. Article
  4. Persistent disparities in black infant mortality across gestational ages in the United States.Journal of perinatology : official journal of the California Perinatal Association · 2024
    Article
  5. Pregnancy exposure to PMEnvironment international · 2024
    Article
  6. Observational
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors.

Amélie BoutinDepartment of Obstetrics and Gynaecology, BC Children's and Women's Hospital and Health Centre, and the University of British Columbia, Vancouver, British Columbia, Canada.ORCID 0000-0003-1907-2920
Sarka LisonkovaDepartment of Obstetrics and Gynaecology, BC Children's and Women's Hospital and Health Centre, and the University of British Columbia, Vancouver, British Columbia, Canada.
Giulia M MuracaDepartment of Obstetrics and Gynaecology, BC Children's and Women's Hospital and Health Centre, and the University of British Columbia, Vancouver, British Columbia, Canada.
Neda RazazClinical Epidemiology Unit, Karolinska Institutet, Stockholm, Sweden.
Shiliang LiuMaternal and Infant Health Section, Public Health Agency of Canada, Ottawa, Ontario, Canada.
Michael S KramerDepartments of Pediatrics and of Epidemiology and Biostatistics, McGill University, Montreal, Quebec, Canada.
K S JosephDepartment of Obstetrics and Gynaecology, BC Children's and Women's Hospital and Health Centre, and the University of British Columbia, Vancouver, British Columbia, Canada.

Funding

CIHR F17-02161CIHR PER-150902
6 · The paper itself

Abstract

backgroundSeveral studies of prenatal determinants and neonatal morbidity and mortality among very preterm births have resulted in unexpected and paradoxical findings. We aimed to compare perinatal death rates among cohorts of very preterm births (24-31 weeks) with rates among all births in these groups (≥24 weeks), using births-based and fetuses-at-risk formulations.

methodsWe conducted a cohort study of singleton live births and stillbirths ≥24 weeks' gestation using population-based data from the United States and Canada (2006-2015). We contrasted rates of perinatal death between women with or without hypertensive disorders, between maternal races, and between births in Canada vs the United States.

resultsBirths-based perinatal death rates at 24-31 weeks were lower among hypertensive than among non-hypertensive women (rate ratio [RR] 0.67, 95% CI 0.65-0.68), among Black mothers compared with White mothers (RR 0.94, 95%CI 0.92-0.95) and among births in the United States compared with Canada (RR 0.74, 95%CI 0.71-0.75). However, overall (≥24 weeks) perinatal death rates were higher among births to hypertensive vs non-hypertensive women (RR 2.14, 95%CI 2.10-2.17), Black vs White mothers (RR 1.86, 95%CI 184-1.88;) and births in the United States vs Canada (RR 1.08, 95%CI 1.05-1.10), as were perinatal death rates based on fetuses-at-risk at 24-31 weeks (RR for hypertensive disorders: 2.58, 95%CI 2.53-2.63; RR for Black vs White ethnicity: 2.29, 95%CI 2.25-2.32; RR for United States vs Canada: 1.27, 95%CI 1.22-1.30).

conclusionStudies of prenatal risk factors and between-centre or between-country comparisons of perinatal mortality bias causal inferences when restricted to truncated cohorts of very preterm births.

Indexed as

AdultBiasBirth RateCanadaCohort StudiesFemaleHumansHypertension, Pregnancy-InducedInfant, NewbornPregnancyPremature BirthRacial GroupsUnited States

Identifiers

PMID34191860
PMCPMC8244917

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.