Almossawi, Ofran;
(2024)
Differences in Paediatric Intensive Care mortality by biological sex - A study of English PICUs.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Background: Global child mortality rates vary by sex, with higher mortality rates generally found in males. However, previous research has shown that this ratio is reversed in infants admitted to Paediatric Intensive Care Units (PICU). I aimed to determine whether female sex is causally linked to higher mortality in PICU. Knowing if sex is a causal factor in mortality will contribute to better assessment of the severity of illness of a child on admission to a PICU. Methods: First, I compiled evidence that may confirm or explain this reversal of the sex ratio in PICU mortality, through a systematic review of studies of mortality in PICU. Second, I created a longitudinal linked dataset that could be used to evaluate whether sex is causally related to mortality in PICU using routine data on >100,000 children admitted to PICU. This linked dataset provided longitudinal records, linked to events prior to and during admission to PICU, and deaths up to five years after discharge from PICU, to enable me to answer the research question. Finally, I compared a number of estimation methods, namely (a) g-computation, (ii) propensity score-based singly and doubly robust methods, and (ii) and targeted learning aided by machine learning, to determine whether the observed sex-ratio reversal in PICU mortality is supported by the data. Results: Female biological sex increased the mortality rate in PICU by up to 0.26% (95% CI -0.05%, 0.57%). In the multiply imputed dataset this estimate was 0.35% (95% CI 0.09%, 0.61%). The reversal in mortality rates in PICU was not explained by collider bias. The collider bias was driving the naïve estimate towards the null. Conclusion: Female biological sex is linked to higher mortality in PICU. Mechanistic reasons underlying this causal relationship, such as response to PICU treatment, need to be studied.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Differences in Paediatric Intensive Care mortality by biological sex - A study of English PICUs |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2024. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| Keywords: | Sex differences, Paediatric Intensive Care, Causal Inference, Data Linkage, Electronic Health Records |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > UCL GOS Institute of Child Health UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > UCL GOS Institute of Child Health > Population, Policy and Practice Dept |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10188590 |
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