An assessment of potential unintended consequences following a national antimicrobial stewardship program in England: An interrupted time series analysis

Violeta Balinskaite*, Sabine Bou-Antoun, Alan Johnson, Alison Holmes, Paul Aylin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Background. The "Quality Premium" (QP) introduced in England in 2015 aimed to financially reward local healthcare commissioners for targeted reductions in primary care antibiotic prescribing. We aimed to evaluate possible unintended clinical outcomes related to this QP. Methods. Using Clinical Practice Research Datalink and Hospital Episode Statistics datasets, we examined general practitioner (GP) consultations (visits) and emergency hospital admissions related to a series of predefined conditions of unintended consequences of reduced prescribing. Monthly age-and sex-standardized rates were calculated using a direct method of standardization. We used segmented regression analysis of interrupted time series to evaluate the impact of the QP on seasonally adjusted outcome rates. Results. We identified 27334 GP consultations and >5 million emergency hospital admissions with predefined conditions. There was no evidence that the QP was associated with changes in GP consultation and hospital admission rates for the selected conditions combined. However, when each condition was considered separately, a significant increase in hospital admission rates was noted for quinsy, and significant decreases were seen for hospital-acquired pneumonia, scarlet fever, pyelonephritis, and complicated urinary tract conditions. A significant decrease in GP consultation rates was estimated for empyema and scarlet fever. No significant changes were observed for other conditions. Conclusions. Findings from this study show that overall there was no significant association between the intervention and unintended clinical consequences, with the exception of a few specific conditions, most of which could be explained through other parallel policy changes or should be interpreted with caution due to small numbers.

Original languageEnglish
Pages (from-to)233-242
Number of pages10
JournalClinical Infectious Diseases
Issue number2
Publication statusPublished - 2 Jul 2019

Bibliographical note

Funding Information:
Financial support. This work was supported by the National Institute for Health Research (NIHR) Policy Research Programme (research to determine the impact of the national antimicrobial stewardship programs on clinical outcomes and patient safety and establish sustainable systems). The Dr Foster Unit is an academic unit in the Department of Primary Care and Public Health, within the School of Public Health, Imperial College London (ICL). The unit receives research funding from the NIHR and Dr Foster Intelligence, an independent health service research organization (a wholly owned subsidiary of Telstra). This work was by supported by the NIHR Health Protection Research Unit (HPRU) in Healthcare Associated Infections and Antimicrobial Resistance at ICL in partnership with Public Health England. The Dr Foster Unit at ICL is affiliated with the NIHR Imperial Patient Safety Translational Research Centre, which is a partnership between the Imperial College Healthcare NHS Trust and ICL. The Department of Primary Care and Public Health at ICL is grateful for support from the Northwest London NIHR Collaboration for Leadership in Applied Health Research and Care and the Imperial NIHR Biomedical Research Centre.

Funding Information:
Potential conflicts of interest. A. H. is the director of NIHR HPRU in Healthcare Associated Infections and Antimicrobial Resistance and a professor at ICL; she also received an honorarium for presenting at the South African Antibiotic Stewardship Programme Annual Workshop, sponsored by Merck (MSD Hoddesdon). P. A. has received grants from Dr Foster (a wholly owned subsidiary of Telstra Health) and NIHR. V. B. has received grants from the UK Department of Health. All other authors report no potential conflicts of interest. All authors have submitted the ICMJE form for disclosure of potential conflicts of interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.


  • Antibiotic prescribing
  • Antimicrobial stewardship programs
  • Interrupted time series
  • Primary and secondary care
  • Unintended consequences


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