Dataset Information

Causal inference in studies of preterm babies: a simulation study.

ABSTRACT:

Objective

Using a simple simulation, we illustrate why associations estimated from studies restricted to preterm births cannot be interpreted causally.

Design, setting and population

Data simulation involving a hypothetical cohort of fetuses who may be healthy or have one or more of four pathological factors (termed A through D, increasing in severity) with known effects on gestational length and risk of mortality. We focus on babies born at ≤32 weeks of gestation.

Methods

We visually represent the simulated population and compare the association between A (which may represent pre-eclampsia) and neonatal death. We then repeat the exercise with D (standing in for chorioamnionitis) as the exposure of interest.

Main outcome measures

Odds ratios of neonatal death in the simulated data.

Results

In most weeks, and for both A and D, the calculated odds ratios are substantially biased and underestimate the true risk of neonatal death associated with each pathology. For example, factor A has a true causal odds ratio of 1.50, yet it appears protective among births ≤32 weeks (estimated crude odds ratio 0.39; gestational age-adjusted odds ratio 0.71).

Conclusions

Among very preterm births, virtually all babies are born with pathologies that increase the risk of adverse outcomes. Hence, babies exposed to one factor (e.g. pre-eclampsia) are compared with babies who have a mix of other pathologies. Such selection bias affects studies carried out among very preterm births (e.g. where pre-eclampsia appears to reduce risk of adverse neonatal outcomes).

Tweetable abstract

Selection bias affects studies of preterm births, complicating interpretation.

SUBMITTER: Snowden JM

PROVIDER: S-EPMC5862739 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

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Publications

Causal inference in studies of preterm babies: a simulation study.

Snowden J M JM Basso O O

BJOG : an international journal of obstetrics and gynaecology 20171030 6

<h4>Objective</h4>Using a simple simulation, we illustrate why associations estimated from studies restricted to preterm births cannot be interpreted causally.<h4>Design, setting and population</h4>Data simulation involving a hypothetical cohort of fetuses who may be healthy or have one or more of four pathological factors (termed A through D, increasing in severity) with known effects on gestational length and risk of mortality. We focus on babies born at ≤32 weeks of gestation.<h4>Methods</h4> ...[more]

PMID: 28941068

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Project description:Aims and objectivesTo explore the experiences of mothers of extremely premature babies during their Neonatal Intensive Care Unit stay and transition home.BackgroundMothers of extremely preterm infants (28 weeks' gestation or less) experience a continuum of regular and repeated stressful and traumatic events, during the perinatal period, during the Neonatal Intensive Care Unit stay, and during transition home.MethodAn interpretive description method guided this study. Ten mothers of extremely premature infants who had been at home for less than six months were recruited via a Facebook invitation to participate in semi-structured telephone interviews exploring their experiences in the Neonatal Intensive Care Unit and the transition home. The data were examined using a six-phase thematic analysis approach. The COREQ checklist has been used.ResultsTwo main themes emerged: (a) things got a bit dire; and (b) feeling a failure as a mother. Participants had a heightened risk of developing a mental disorder from exposure to multiple risk factors prior to and during birth, as well as during the postnatal period in the Neonatal Intensive Care Unit and their infant's transition to home. Mothers highlighted the minimal support for their mental health from healthcare professionals, despite their regular and repeated experience of traumatic events.ConclusionThe mothers were at high risk of developing post-traumatic stress symptoms and/or other mental health issues. Of note, study participants relived the trauma of witnessing their infant in the Neonatal Intensive Care Unit, demonstrated hypervigilance behaviour and identified lack of relevant support needed when their infant was at home.Relevance to clinical practiceThis study highlights the need for nurses to include a focus on the mothers' psychosocial needs. Supporting maternal mental health both improves maternal well-being and enables mothers to be emotionally available and responsive to their extremely preterm infant.

Dataset Information

Causal inference in studies of preterm babies: a simulation study.

Objective

Design, setting and population

Methods

Main outcome measures

Results

Conclusions

Tweetable abstract

Publications

Causal inference in studies of preterm babies: a simulation study.

Similar Datasets

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