The hospital standardised mortality ratio: a powerful tool for Dutch hospitals to assess their quality of care?
OPEN ACCESS- 1Dr Foster Unit, Faculty of Medicine, Imperial College, London, UK
- 2Prismant, Utrecht, The Netherlands
- 3de Praktijk Index, Ondiep Zuidzijde, Utrecht, The Netherlands
- 4RIVM National Institute for Public Health and the Environment and Tranzo, Tilburg University, Bilthoven, The Netherlands
- 5Division of Health and Social Care Research, James Clerk Maxwell Building, King's College London, London, UK
- 6Dr Foster Intelligence, London, UK
- Correspondence to Brian Jarman, Dr Foster Unit, Faculty of Medicine, Imperial College London EC1A 9LA, UK; b.jarman{at}imperial.ac.uk
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Contributors All the authors have been involved in writing, reading and commenting on the manuscript. BJ, DP, PA, AB and SJ were involved in developing the model. BJ is the guarantor of the content.
- Accepted 21 July 2009
Abstract
Aim of the study To use the hospital standardised mortality ratio (HSMR), as a tool for Dutch hospitals to analyse their death rates by comparing their risk-adjusted mortality with the national average.
Method The method uses routine administrative databases that are available nationally in The Netherlands—the National Medical Registration dataset for the years 2005–2007. Diagnostic groups that led to 80% of hospital deaths were included in the analysis. The method adjusts for a number of case-mix factors per diagnostic group determined through a logistic regression modelling process.
Results In The Netherlands, the case-mix factors are primary diagnosis, age, sex, urgency of admission, length of stay, comorbidity (Charlson Index), social deprivation, source of referral and month of admission. The Dutch HSMR model performs well at predicting a patient's risk of death as measured by a c statistic of the receiver operating characteristic curve of 0.91. The ratio of the HSMR of the Dutch hospital with the highest value in 2005–2007 is 2.3 times the HSMR of the hospital with the lowest value.
Discussion Overall hospital HSMRs and mortality at individual diagnostic group level can be monitored using statistical process control charts to give an early warning of possible problems with quality of care. The use of routine data in a standardised and robust model can be of value as a starting point for improvement of Dutch hospital outcomes. HSMRs have been calculated for several other countries.
Footnotes
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Funding There was no separate funding for this study. BJ, AB and PA are employed within the Dr Foster Unit at Imperial College London (BJ, part-time), which is partly funded by a grant from Dr Foster Intelligence (an independent health service research organisation). The unit is also partly funded for its HSMR work by the Rx Foundation of Cambridge, Massachusetts, USA, and is affiliated with the Centre for Patient Safety and Service Quality at Imperial College Healthcare NHS Trust, which is funded by the National Institute of Health Research. The Department of Primary Care and Social Medicine is grateful for support from the National Institute for Health Research Biomedical Research Centre Funding Scheme.
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Competing interests None.
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Provenance and peer review Not commissioned; externally peer reviewed.
