both hospital and nonhospital VTE-related mortality and therefore may not fully reflect the impact that introduction of the VTE risk assessment tool within the NHS in England has had.

Conclusion
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This study shows reductions in VTE-related secondary diagnoses and readmissions among adults admitted to hospital, and a reduction in VTE-related mortality, since the introduction of a national VTE risk assessment screening tool in England. Despite some study limitations, the findings suggest that the concerted effort that has been made by NHS England to improve prevention of hospital-acquired VTE has been successful and indicates that introduction of compulsory VTE risk assessment in hospitals positively impacts patient outcomes.

Acknowledgements
================

D.C. would like to thank Victoria Serra-Sastre of City University, London, and Charlie Nicholls and Carl Tilling of Sanofi for helpful discussions and advice. JenniferStewart, MSc (QXV Communications, UK) provided editorial support.

Hospital Episode Statistics data were provided under reuse licence by Harvey Walsh Limited, Copyright 2012, and were reused with the permission from the Health and Social Care Information Centre. All rights reserved.

D.C. has subsequently become a permanent employee of Sanofi.

Ethical approval was not required.

Due to the nature of this study there are no recognized checklists that were applicable.

Data sets and technical details are available from the corresponding author at David.Catterick\@sanofi.com

Conflicts of interest
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D.C. held a paid student internship at Sanofi, UK, during the study period (This study was conducted in part fulfilment of an MSc in Economic Evaluation in Healthcare from City University, London, and was supported by Sanofi as part of the author\'s education. Sanofi provided assistance in access to statistical