fullPIERS: Pre-eclampsia Integrated Estimate of RiSk
Pre-eclampsia is a leading cause of maternal deaths. These deaths mainly result from eclampsia, uncontrolled hypertension, or systemic inflammation. The fullPIERS model was developed and validated with the aim of identifying the risk of fatal or life-threatening complications in women with pre-eclampsia within 48 h of hospital admission for the disorder.

The fullPIERS model was developed and internally validated in a prospective, multicentre study in women who were admitted to tertiary obstetric centres with pre-eclampsia or who developed pre-eclampsia after admission. The outcome of interest was maternal mortality or other serious complications of pre-eclampsia. Routinely reported and informative variables were included in a stepwise backward elimination regression model to predict the adverse maternal outcome. Performance was assessed using the area under the curve (AUC) of the receiver operating characteristic (ROC). Standard bootstrapping techniques were used to assess potential overfitting.

261 of 2023 women with pre-eclampsia had adverse outcomes at any time after hospital admission (106 [5%] within 48 h of admission). Predictors of adverse maternal outcome included gestational age, chest pain or dyspnoea, oxygen saturation, platelet count, and creatinine and aspartate transaminase concentrations. The fullPIERS model predicted adverse maternal outcomes within 48 h of study eligibility (AUC ROC 0·88, 95% CI 0·84–0·92). There was no significant overfitting. fullPIERS performed well (AUC ROC >0·7) up to 7 days after eligibility.

The fullPIERS model identifies women at increased risk of adverse outcomes up to 7 days before complications arise and can thereby modify direct patient care (eg, timing of delivery, place of care), improve the design of clinical trials, and inform biomedical investigations related to pre-eclampsia.
Research authors: Peter von Dadelszen, Beth Payne, Jing Li, J Mark Ansermino, Fiona Broughton Pipkin, Anne-Marie Côté, M Joanne Douglas, Andrée Gruslin, Jennifer A Hutcheon, K S Joseph, Phillipa M Kyle, Tang Lee, Pamela Loughna, Jennifer M Menzies, Mario Merialdi, Alexandra L Millman, M Peter Moore, Jean-Marie Moutquin, Annie B Ouellet, Graeme N Smith, James J Walker, Keith R Walley, Barry N Walters, Mariana Widmer, Shoo K Lee, James A Russel, Laura A Magee, for the PIERS study group
Details Formula Study characteristics Files & References
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Model ID
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MeSH terms
  • Pre-Eclampsia
  • Model type
    Logistic regression (Calculation)
    No Formula defined yet
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    Additional information

    Between Sept 1, 2003, and Jan 31, 2010, data for 2023 women (2221 fetuses) were entered into the fullPIERS database from eight international sites. There were 261 (13%) combined adverse maternal outcomes at any time after eligibility. By comparison with women who did not develop adverse outcomes, women who did were of lower gestational age at eligibility, and were less likely to be either parous, to smoke during the pregnancy, or to be eligible on the basis of hyperuricaemia. They were more likely to develop HELLP syndrome and to receive both antihypertensive drugs or antenatal corticosteroids, or both (for either fetal lung maturation or HELLP). Maternal blood pressure indices, dipstick proteinuria, and aspartate transaminase concentration were higher in women who developed adverse outcomes, whereas platelet counts were lower. The eligibility-todelivery interval did not vary between groups, except in women eligible at less than 34 weeks’ gestation. Such women who developed outcomes had briefer eligibility to-delivery intervals. Women who developed adverse outcomes were more likely to receive MgSO4 during their clinical course and to deliver babies earlier and of lower birthweight. Perinatal and infant mortality did not differ significantly between groups.


    Study Population

    Total population size: 2023
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    Females: {{ model.numberOfFemales }}

    Categorical characteristics

    Name Subset / Group Nr. of patients
    Women with adverse outcomes N=261 Maternal age (years) 31
    Gestational age at eligibillity (weeks) 33.9
    Gestational age at eligibillity <34 weeks 133
    Multiple pregnancy 36
    Parity ≥1 72
    Smoking during this pregnancy 26
    Hypertension and proteinuria 178
    Hypertension and hyperuricaemia 21
    HELLP without hypertension or proteinuria 23
    Superimposed pre-eclampsia 39
    Peak: Mean arterial pressure (mmHg) 123
    Peak: Systolic blood pressure (mmHg) 170
    Peak: diastolic blood pressure (mmHg) 104
    Worst dipstick proteinuria (+) 3
    Lowest platelet count (x10^9/L) 170
    Highest aspartate transaminase (U/L) 31
    Corticosteroid administration 114
    Antihypertensive drugs administered 214
    MgSO4 administered 161
    Admission-to-delivery interval, all cases (days) 2
    Admission-to-delivery interval <34 weeks (days) 4
    Gestational age at delivery (weeks) 34.7
    Birthweight lower than third percentile 22
    Intrauterine fetal death ≥20⁺⁰ weeks or ≥500 g 4
    Neonatal death before 28 days 5
    Infant death before hospital discharge or 6 weeks 7
    Women without adverse outcomes N=1762 Maternal age (years) 31
    Gestational age ate eligibility (weeks) 33.9
    gestational age at eligibility <34 weeks 503
    Multiple pregnancy 156
    Parity ≥1 509
    Smoking during this pregnancy 223
    Hypertension and proteinuria 1164
    Hypertension and hyperuricaemia 303
    HELLP without hypertension or proteinuria 29
    Superimposed pre-eclampsia 266
    Peak: Mean arterial pressure (mm Hg) 120
    Peak: Systolic blood pressure (mm Hg) 160
    Peak: Diastolic blood pressure (mm Hg) 101
    Worst dipstick proteinuria (+) 2
    Lowest platelet count (x10^9/L) 194
    Highest aspartate transaminase (U/L) 26
    Corticosteroid administration 436
    Antihypertensive drugs administered 1167
    MgSO4 administered 529
    Admission-to-delivery interval, all cases (days) 2
    Admission-to-delivery interval, <34⁺⁰ weeks (days) 5
    Gestational age at delivery (weeks) 37.0
    Birthweight (g) 2685
    Birthweight lower than third percentile 143
    Intrauterine fetal death, ≥20⁺⁰ weeks or ≥500 g 16
    Neonatal death, before 28 days 15
    Infant death before hospital discharge or 6 weeks 19
    fullPIERS: Pre-eclampsia Integrated Estimate of RiSk
    Refer to Intended Use for instructions before use
    Evidencio B.V., Irenesingel 19, 7481 GJ, Haaksbergen, the Netherlands

    The risk of adverse maternal outcomes is

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    The risk of adverse maternal outcomes is

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    Outcome stratification

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    Result interpretation

    External validation studies showed the usefulness of the fullPIERS model in discriminating between patients at high and low risk of adverse maternal outcomes within 48 hours up to a week after assessment.

    A threshold of ≥30% risk is suggested as a threshold to rule-in the outcome.

    The model can be used to aid clinicans in managing women with pre-eclampsia in similar settings and to make decisions such as transfer to higher care units and delivery. 

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    Calculations alone should never dictate patient care, and are no substitute for professional judgement. See our full disclaimer.

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