Start and end dates

From 2009 - ongoing


Project summary


Making healthcare safer is a worldwide movement, and the first step in improving standards is measurement. As part of our involvement in the NIHR North West London Patient Safety Research Collaboration , we process large routine databases covering general practice and hospitals to define indicators of patient safety. We mostly use Hospital Episodes Statistics (HES) data but are increasingly exploring the Clinical Practice Research Datalink (CPRD, a primary care database linked to HES and death registrations). For our related work in primary care see our research page Effective use of patient data.

Further projects funded by Dr Foster include:

  • Trouble-free pathways:  in this project we investigate the proportion of patients whose journey through the healthcare system is without adverse events as a potential, patient-centered indicator aligned directly with the goal of patient safety-freedom from harm. We are also currently looking to apply this indicator to Australian hospital data.
  • Association between patient and general practice characteristics and unplanned first-time admissions for cancer:  in this project we attempted to identify patient and general practice (GP) characteristics associated with emergency (unplanned) first admissions for cancer in secondary care.


  • To derive indicators of patient safety in general practice, specifically around missed or delayed diagnosis
  • To derive new hospital indicators of patient safety
  • To extend our English work to databases from other countries, such as Germany and Australia


Peer-reviewed publications

  • King A, Bottle A, Faiz O, Aylin P. Investigating Adverse Event Free Admissions in Medicare Inpatients as a Patient Safety Indicator. Ann Surg 2016 May 17 PubMed
  • Bouras G, Burns EM, Howell A, Bottle R, Athanasiou T, Darzi A. Risk of Post-Discharge Venous Thromboembolism and Associated Mortality in General Surgery: A Population-Based Cohort Study Using Linked Hospital and Primary Care Data in England PLOS One 2015;10(12):e0145759 PubMed
  • Bouras G, Markar SR, Burns EM, Mackenzie HA, Bottle A, Athanasiou T, Hanna GB, Darzi A. Linked Hospital and Primary Care Database Analysis of the Incidence and Impact of Psychiatric Morbidity Following Gastrointestinal Cancer Surgery in England. Ann Surg 2016;264(1):93-9 PubMed
  • Tsang C, Bottle A, Majeed A, Aylin Pet al., 2013, Cancer diagnosed by emergency admission in England: an observational study using the general practice research database, BMC HEALTH SERVICES RESEARCH, Vol: 13, ISSN: 1472-6963 Publisher's link.
  • Tsang C, Bottle A, Majeed A, Aylin Pet al., 2013, Adverse events recorded in English primary care: observational study using the General Practice Research Database, BRITISH JOURNAL OF GENERAL PRACTICE, Vol: 63, Pages: E534-E542, ISSN: 0960-1643 Publisher's link.
  • Bottle A, Tsang C, Parsons C, Majeed A, Soljak M, Aylin P. Association between patient and general practice characteristics and unplanned first-time admissions for cancer: observational study. Br J Cancer 2012;107(8):1213-1219 PubMed
  • Bottle A, Aylin P. Application of AHRQ patient safety indicators to English hospital data. Qual Saf Health Care 2009; 18: 303-308 PubMed
  • Bottle A, Aylin P. How NHS trusts could use patient safety indicators to improve care. Health Care Risk Report 2008; May: 12-14