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What factors predict differences in infant and perinatal mortality in primary care trusts in England? A prognostic model

BMJ 2009; 339 doi: (Published 04 August 2009) Cite this as: BMJ 2009;339:b2892
  1. Nick Freemantle, professor of clinical epidemiology and biostatistics1,
  2. J Wood, lecturer in statistics2,
  3. C Griffin, consultant in public health3,
  4. P Gill, reader in primary care research1,
  5. M J Calvert, senior lecturer1,
  6. A Shankar, research associate4,
  7. J Chambers, director of public health5,
  8. C MacArthur, professor of maternal and child epidemiology1
  1. 1School of Health & Population Sciences, University of Birmingham, Birmingham B15 2TT
  2. 2Department of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ
  3. 3Sandwell Primary Care Trust, Kingston House, West Bromwich B70 9LD
  4. 4Health and Social Surveys Research Group, Department of Epidemiology and Public Health, UCL-Gower Street Campus, London WC1E 6BT
  5. 5Heart of Birmingham PCT, Edgbaston, Birmingham B16 9NX
  1. Correspondence to: N Freemantle N.Freemantle{at}
  • Accepted 11 March 2009


Objective To identify predictors of perinatal and infant mortality variations between primary care trusts (PCTs) and identify outlier trusts where outcomes were worse than expected.

Design Prognostic multivariable mixed models attempting to explain observed variability between PCTs in perinatal and infant mortality. We used these predictive models to identify PCTs with higher than expected rates of either outcome.

Setting All primary care trusts in England.

Population For each PCT, data on the number of infant and perinatal deaths, ethnicity, deprivation, maternal age, PCT spending on maternal services, and “Spearhead” status.

Main outcome measures Rates of perinatal and infant mortality across PCTs.

Results The final models for infant mortality and perinatal mortality included measures of deprivation, ethnicity, and maternal age. The final model for infant mortality explained 70% of the observed heterogeneity in outcome between PCTs. The final model for perinatal mortality explained 80.5% of the between-PCT heterogeneity. PCT spending on maternal services did not explain differences in observed events. Two PCTs had higher than expected rates of perinatal mortality.

Conclusions Social deprivation, ethnicity, and maternal age are important predictors of infant and perinatal mortality. Spearhead PCTs are performing in line with expectations given their levels of deprivation, ethnicity, and maternal age. Higher spending on maternity services using the current configuration of services may not reduce rates of infant and perinatal mortality.


  • Contributors: CG, NF, and JC conceived the idea for the study. All authors contributed to the design of the study, the interpretation of the results, and the writing of the paper. NF and JW designed and conducted the statistical analyses. NF is the guarantor.

  • Funding: Funded by the Birmingham Health and Wellbeing partnership.

  • Competing interests: None declared.

  • Ethical approval: Not needed for this study.

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: and

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