A report from #BlueJC: Can measuring angiogenic factors help with predicting preterm pre-eclampsia in low-risk women?


Paper discussed: Myers J, Kenny L, McCowan L, Chan E, Dekker G, Poston L, Simpson N, North R. Angiogenic factors combined with clinical risk factors to predict preterm pre-eclampsia in nulliparous women: a predictive test accuracy study. BJOG 2013;120:1215–23.

Location: Twitter Number of participants: 21

Date of journal club: 14 October 2013 Number of tweets: 171

Paper summary:

Participants Low-risk nulliparous women
Intervention Screening for pre-eclampsia using clinical risk factors, uterine artery Doppler ultrasound and angiogenic markers (Placental growth factor [PlGF], sFlt-1 and endoglin)
Comparison Screening for pre-eclampsia with clinical risk factors alone
Outcomes Preterm pre-eclampsia (before 37+0 weeks of gestation)
Study design Predictive test accuracy study using a prospective, multicentre and multinational cohort
Results PlGF measured at 14–16 weeks improved the identification of women at risk of pre-eclampsia

Research literacy

Was there reporting bias?

The primary outcome was not stated in the study protocol (http://bit.ly/ACTRNScope). Biomarkers may have been selectively published according to the results, which may constitute reporting bias.

Was the prediction model over-optimistic?

Inclusion of a relatively high number of potentially predictive variables (n > 14) and a low number of outcome events (n = 47) risks over-optimism and ‘over-fitting’ of the resulting model (Moons et al., Heart 2012;98:691–8).

Feedback on the study

Economic analysis will be helpful

This study demonstrated an example of collaboration between pharmaceutical companies and academia. An economic analysis may highlight the potential cost-effectiveness of using these biomarkers. Existing analyses show that screening tests need to be highly accurate and cheap to be cost effective (Meads et al., Health Technol Assess 2008;12:1–270).

Informative presentation of results

Comparisons were made between the applied predictive ability of the final model and the current National Institute for Health and Care Excellence tool (Table 5 in paper Myers et al.), which was simple yet informative. However, there is a trade-off between specificity and sensitivity that affects the clinical usefulness of the model.

Controversies

Is this a pilot study?

Following publication, collaborators clarified that this was a pilot study (http://bit.ly/SCOPEchat) that preceded the full report of the entire SCOPE cohort. Some participants raised whether this constituted scientific salami slicing.

Take home message

The combination of clinical risk factors with angiogenic markers in the second trimester reported in the study needs enhancement through publication of the results of all biomarkers measured for preterm pre-eclampsia screening.

Acknowledgements

MB wrote the first draft of the report. Both authors contributed to subsequent drafts. We are grateful for all contributions to this journal club. A transcript and a list of contributors can be viewed at http://bit.ly/16ixzBz.

  • M Blacka & EYL Leungb

  • aUniversity Department of Obstetrics and Gynaecology, Aberdeen Maternity Hospital, Aberdeen, UK

  • bWomen's Health Research Unit, Queen Mary, University of London, UK

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