Associations between Stroke Mortality and Weekend Working by Stroke Specialist Physicians and Registered Nurses: Prospective Multicentre Cohort Study
Authors: Benjamin D. Bray mail, Salma Ayis, James Campbell, Geoffrey C. Cloud, Martin James, Alex Hoffman, Pippa J. Tyrrell, Charles D. A. Wolfe, Anthony G. Rudd
Abstract
Background
Observational studies have reported higher mortality for patients admitted on weekends. It is not known whether this “weekend effect” is modified by clinical staffing levels on weekends. We aimed to test the hypotheses that rounds by stroke specialist physicians 7 d per week and the ratio of registered nurses to beds on weekends are associated with mortality after stroke.
Methods and Findings
We conducted a prospective cohort study of 103 stroke units (SUs) in England. Data of 56,666 patients with stroke admitted between 1 June 2011 and 1 December 2012 were extracted from a national register of stroke care in England. SU characteristics and staffing levels were derived from cross-sectional survey. Cox proportional hazards models were used to estimate hazard ratios (HRs) of 30-d post-admission mortality, adjusting for case mix, organisational, staffing, and care quality variables. After adjusting for confounders, there was no significant difference in mortality risk for patients admitted to a stroke service with stroke specialist physician rounds fewer than 7 d per week (adjusted HR [aHR] 1.04, 95% CI 0.91–1.18) compared to patients admitted to a service with rounds 7 d per week. There was a dose–response relationship between weekend nurse/bed ratios and mortality risk, with the highest risk of death observed in stroke services with the lowest nurse/bed ratios. In multivariable analysis, patients admitted on a weekend to a SU with 1.5 nurses/ten beds had an estimated adjusted 30-d mortality risk of 15.2% (aHR 1.18, 95% CI 1.07–1.29) compared to 11.2% for patients admitted to a unit with 3.0 nurses/ten beds (aHR 0.85, 95% CI 0.77–0.93), equivalent to one excess death per 25 admissions. The main limitation is the risk of confounding from unmeasured characteristics of stroke services.
Conclusion
Mortality outcomes after stroke are associated with the intensity of weekend staffing by registered nurses but not 7-d/wk ward rounds by stroke specialist physicians. The findings have implications for quality improvement and resource allocation in stroke care.
Citation:Bray BD, Ayis S, Campbell J, Cloud GC, James M, et al. (2014) Associations between Stroke Mortality and Weekend Working by Stroke Specialist Physicians and Registered Nurses: Prospective Multicentre Cohort Study. PLoS Med 11(8): e1001705. doi:10.1371/journal.pmed.1001705
Academic Editor:Gordon Lowe, University of Glasgow, United Kingdom
Received:December 13, 2013;Accepted:July 10, 2014;Published:August 19, 2014
Copyright:© 2014 Bray et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability:The authors confirm that, for approved reasons, some access restrictions apply to the data underlying the findings. Data on the organisation of stroke services collected in the Sentinel Stroke Organisational Audit is available for unrestricted download: http://www.rcplondon.ac.uk/projects/ssnap-acute-organisational-audit. Patient-level data in aggregate form (hospital-level) collected in SINAP is available for unrestricted download at: http://www.rcplondon.ac.uk/projects/stroke-improvement-national-audit-programme-sinap. Researchers may apply for access to anonymised patient-level data, subject to an approvals process. For further information: http://www.rcplondon.ac.uk/projects/sentinel-stroke-national-audit-programme.
Funding: The SINAP audit is commissioned by the Healthcare Quality Improvement Partnership on behalf of the Department of Health in England. The National Sentinel Stroke Audit 2010 was commissioned by the Healthcare Quality Improvement Partnership on behalf of the Department of Health in England. No specific funding from any source was sought for this study. The research was supported by the National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy's and St. Thomas' NHS Foundation Trust and King's College London. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health. No funding bodies had any role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests:AR is National Clinical Director for Stroke, NHS England. AH and JC are employed in managing and carry out SINAP and national audit of stroke care in England. PJT, AH, AR, GCC, and MJ are members of the Royal College of Physicians (London) Intercollegiate Working Party on Stroke. The other authors have no conflicts of interest to declare.
Abbreviations:aHR, adjusted hazard ratio; HDU, high dependency unit; HR, hazard ratio; ICU, intensive care unit; OCSP, Oxfordshire Community Stroke Project; SINAP, Stroke Improvement National Audit Programme; SU, stroke unit
