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The impact of pre-eclampsia definitions on the identification of adverse outcome risk in hypertensive pregnancy – analyses from the CHIPS trial (Control of Hypertension in Pregnancy Study)

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the CHIPS Study Group

Original languageEnglish
Pages (from-to)1373-1382
Number of pages10
JournalBJOG: An International Journal of Obstetrics and Gynaecology
Volume128
Issue number8
DOIs
PublishedJul 2021

Bibliographical note

Funding Information: Supported by a grant (MCT 87522) from the Canadian Institutes of Health Research. The funder played no role in conducting the research or writing the paper. Laura Magee received salary support from the Michael Smith Foundation for Health Research, Vancouver, Canada and Peter von Dadelszen from the Canadian Institutes of Health Research. We sincerely thank all of the women who gave of themselves by participating in CHIPS. We wish to extend thanks to APEC (https://action-on-pre-eclampsia.org.uk/) and the Preeclampsia Foundation (https://www.preeclampsia.org/) for their steadfast commitment to ensuring that the patient perspective is integrated into pregnancy hypertension research. Funding Information: Supported by a grant (MCT 87522) from the Canadian Institutes of Health Research. The funder played no role in conducting the research or writing the paper. Laura Magee received salary support from the Michael Smith Foundation for Health Research, Vancouver, Canada and Peter von Dadelszen from the Canadian Institutes of Health Research. Publisher Copyright: © 2020 John Wiley & Sons Ltd. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

King's Authors

Abstract

Objective: To examine the association between pre-eclampsia definition and pregnancy outcome. Design: Secondary analysis of Control of Hypertension in Pregnancy Study (CHIPS) trial data. Setting: International multicentre randomised controlled trial (RCT). Population: In all, 987 women with non-severe non-proteinuric pregnancy hypertension. Methods: We evaluated the association between pre-eclampsia definitions and adverse pregnancy outcomes, stratified by hypertension type and blood pressure control. Main outcome measures: Main CHIPS trial outcomes: primary (perinatal loss or high-level neonatal care for >48 hours), secondary (serious maternal complications), birthweight <10th centile, severe maternal hypertension, delivery at <34 or <37 weeks, and maternal hospitalisation before birth. Results: Of 979/987 women with informative data, 280 (28.6%) progressed to pre-eclampsia defined restrictively by new proteinuria, and 471 (48.1%) to pre-eclampsia defined broadly as proteinuria or one/more maternal symptoms, signs or abnormal laboratory tests. The broad (versus restrictive) definition had significantly higher sensitivities (range 62–79% versus 36–50%), lower specificities (range 53–65% versus 72–82%), and similar or higher diagnostic odds ratios and ‘true-positive’ to ‘false-positive’ ratios. Stratified analyses showed similar results. Addition of available fetoplacental manifestations (stillbirth or birthweight <10th centile) to the broad pre-eclampsia definition improved sensitivity (74–87%). Conclusions: A broad (versus restrictive) pre-eclampsia definition better identifies women who develop adverse pregnancy outcomes. These findings should be replicated in a prospective study within routine healthcare to ensure that the anticipated increase in surveillance and intervention in a larger number of women with pre-eclampsia is associated with improved outcomes, reasonable costs and congruence with women's values. Tweetable abstract: A broad (versus restrictive) pre-eclampsia definition better identifies the risk of adverse pregnancy outcomes.

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