PREP-L: Risk of complications in Early-onset Pre-eclampsia
The PREP-L model is an externally validated logistic regression based prognostic model predicting the risk of complications in early-onset pre-eclampsia at discharge. It was developed together with the PREP-S model, which is a survival regression model and allows risk prediction over time. 

An evaluation of the impact of the PREP models in clinical practice is still required. 

PREP models can be used to obtain predictions of adverse maternal outcome risk, including early preterm delivery, by 48 hours (PREP-S) and by discharge (PREP-L), in women with early onset pre-eclampsia in the context of current care.

Note: The PREP-L and PREP-S models can be calculated together in the composite model. 
Research authors: Shakila Thangaratinam, John Allotey, Nadine Marlin, Julie Dodds, Fiona Cheong-See, Peter von Dadelszen, Wessel Ganzevoort, Joost Akkermans, Sally Kerry, Ben W. Mol, Karl G.M. Moons, Richard D. Riley, Khalid S. Khan
Details Formula Study characteristics Files & References
Model author
Model ID
Revision date
MeSH terms
  • Pre-Eclampsia
  • Maternal Age
  • Gestational Age
  • Pregnancy
  • Model type
    Logistic regression (Calculation)

    Additional information

    Women with confirmed early onset pre-eclampsia were recruited from 53 maternity units in the UK to a large prospective cohort study (PREP-946) for development of prognostic models for the overall risk of experiencing a complication using logistic regression (PREP-L), and for predicting the time to adverse maternal outcome using a survival model (PREP-S). External validation of the models were carried out in a multinational cohort (PIERS-634) and another cohort from the Netherlands (PETRA-216). Main outcome measures were C-statistics to summarise discrimination of the models and calibration plots and calibration slopes.

    Study Population

    Total population size: 954
    Males: {{ model.numberOfMales }}
    Females: {{ model.numberOfFemales }}

    Continuous characteristics

    Name Mean SD Unit
    Maternal age 30.2 6.1 Years
    Gestational age at diagnosis 30.5 2.9 Weeks
    systolic blood pressure 159 19 mmHg
    Diastolic blood pressure 99 12 mmHg
    Oxygen saturation by pulse oximetry 98 2 %
    Haemoglobin 11.9 1.3 g/L
    Platelet ount 226 78 10^9/L
    Alanine transaminase 31 71 U/L
    Serum uric acid 0.6 2.7 umol/L
    Serum urea 4.6 4.4 mmol/L
    Serum creatinine 61.0 17.8 μmol/L
    Urine PCR 273 492 mg/mmol

    Categorical characteristics

    Name Subset / Group Nr. of patients
    Number of fetuses in pregnancy Singleton 866
    Twins 83
    Triplets 5
    Parity 0 551
    1 207
    2 109
    3 55
    4 20
    5-9 12
    Medical history None 601
    At least one condition 251
    Two or more conditions 101
    Chronic hypertension 139
    Renal disease 30
    Previous history of pre-eclampsia 169
    Autoimmune disease 18
    Diabetes mellitus 109
    Symptoms Headache and/or visual disturbance 382
    Epigastric pain, nausea and/or vomiting 202
    Chest pain and/or breathlessness 60
    Bedside examination and tests Clonus 95
    Exaggerated tendon reflexes 147
    Oxyggen saturation: abnormal (<94%) 4
    Urine dipstick None/Trace 39
    1+ 170
    2+ 314
    3+ 306
    ≥4 106
    Treatment provided Any anti-hypertensive therapy 753
    Oral anti-hypertensive therapy 734
    Parenteral anti-hypertensive therapy 111
    Parental magnesium sulfate 144
    PREP-L: Risk of complications in Early-onset Pre-eclampsia
    Refer to Intended Use for instructions before use
    Evidencio B.V., Irenesingel 19, 7481 GJ, Haaksbergen, the Netherlands

    Related files

    No related files available

    Supporting Publications

    Predicted risk of adverse event by the time of discharge is:

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    Predicted risk of adverse event by the time of discharge is:

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    Outcome stratification

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    Conditional information

    Result interpretation

    The PREP-L model is best to be used together with the PREP-S model. With good agreement between the predicted and observed risk of complications in the PREP-S at 48 hours in the low- and intermediate-risk groups, women with a predicted probability of complications below 50% can avoid unnecessary transfer to tertiary units. Women categorised to be low risk by the PREP-L model could be followed-up in an outpatient setting, with high- and very high-risk women monitored as inpatients with regular intensive monitoring.

    Provision of personalised risk information allows parents to have the opportunity to discuss the expected outcomes. It is important to recognise that all prediction models in this field, including the PREP models, provides risk estimates in the context of current care and clinical management decisions. The models are not designed to guide clinicians’ decisions on choice of management such as timing of delivery, administration of anti-hypertensives and magnesium sulfate. A woman with a low predicted risk should be viewed as an individual with low outcome risk if current care pathways are used, as it may be the clinical care that results in her low-risk status.

    An important note is that the PREP models need proper evaluation of their impact in clinical practice. Thresholds for interventions (such as transfer to tertiary care units, or hospital admission) need to be established. 

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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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