Table F.9Calculating PPV and NPV using a BMI of 27 kg/m2 or more as a risk factor screen

ParameterValueSource
High-risk BMI proportion0.358ONSa
Proportion of gestational diabetes high-risk BMI0.362Davey and Hamblin (2001)831
Births645 835ONS
High-risk BMI births231 209Calculated
Low-risk BMI births414 624Calculated
Gestational diabetes prevalence0.035GDG estimate
Gestational diabetes births22 604Calculated
High-risk BMI gestational diabetes births8 183Calculated
Low-risk BMI gestational diabetes births14 421Calculated
PPV (8183/231 209)3.5%Calculated
NPV (400 203/414 624)96.5%Calculated
a

ONS data are based on proportions with BMI > 25 kg/m2 (see earlier discussion).

From: Appendix F, Economic model: screening and treatment of gestational diabetes

Cover of Antenatal Care
Antenatal Care: Routine Care for the Healthy Pregnant Woman.
NICE Clinical Guidelines, No. 62.
National Collaborating Centre for Women's and Children's Health (UK).
London: RCOG Press; 2008 Mar.
Copyright © 2008, National Collaborating Centre for Women’s and Children’s Health.

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