title: The magnitude and mechanisms of the weekend effect in hospital admissions: A protocol for a mixed methods review incorporating a systematic review and framework synthesis.
abstract: BACKGROUND
  Growing literature has demonstrated that patients admitted to hospital during weekends tend to have less favourable outcomes, including increased mortality, compared with similar patients admitted during weekdays. Major policy interventions such as the 7-day services programme in the UK NHS have been initiated to reduce this weekend effect, although the mechanisms behind the effect are unclear. Here, we propose a mixed methods review to systematically examine the literature surrounding the magnitude and mechanisms of the weekend effect.
  
  
  METHODS
  MEDLINE, CINAHL, HMIC, EMBASE, EthOS, CPCI and the Cochrane Library were searched from Jan 2000 to April 2015 using terms related to 'weekends or out-of-hours' and 'hospital admissions'. The 5404 retrieved records were screened by the review team, and will feed into two component reviews: a systematic review of the magnitude of the weekend effect and a framework synthesis of the mechanisms of the weekend effect. A repeat search of MEDLINE will be conducted mid-2016 to update both component reviews. The systematic review will include quantitative studies of non-specific hospital admissions. The primary outcome is the weekend effect on mortality, which will be estimated using a Bayesian random effects meta-analysis. Weekend effects on adverse events, length of hospital stay and patient experience will also be examined. The development of the framework synthesis has been informed by the initial scoping of the literature and focus group discussions. The synthesis will examine both quantitative and qualitative studies that have compared the processes and quality of care between weekends and weekdays, and explicate the underlying mechanisms of the weekend effect.
  
  
  CONCLUSIONS
  The weekend effect is a complex phenomenon that has major implications for the organisation of health services. Its magnitude and underlying mechanisms have been subject to heated debate. Published literature reviews have adopted restricted scopes or methods and mainly focused on quantitative evidence. This proposed review intends to provide a comprehensive and in-depth synthesis of diverse evidence to inform future policy and research aiming to address the weekend effect.
  
  
  BACKGROUND
  PROSPERO 2016: CRD42016036487.
authors.affiliation: Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK. Y-F.Chen@warwick.ac.uk.|Warwick Centre for Applied Health Research & Delivery, Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK. Y-F.Chen@warwick.ac.uk.
authors.forename: Yen-Fu
authors.initials: YF
authors.lastname: Chen
authors.affiliation: Queen Elizabeth Hospital Birmingham and University of Birmingham, Birmingham, UK.
authors.forename: Amunpreet
authors.initials: A
authors.lastname: Boyal
authors.affiliation: Department of Health Sciences, University of Leicester, Leicester, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Sutton
authors.affiliation: Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK.
authors.forename: Xavier
authors.initials: X
authors.lastname: Armoiry
authors.affiliation: Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK.|Warwick Centre for Applied Health Research & Delivery, Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK.
authors.forename: Samuel
authors.initials: S
authors.lastname: Watson
authors.affiliation: Queen Elizabeth Hospital Birmingham and University of Birmingham, Birmingham, UK.
authors.forename: Julian
authors.initials: J
authors.lastname: Bion
authors.affiliation: Department of Health Sciences, University of Leicester, Leicester, UK.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Tarrant
mesh_terms: D039602:After-Hours Care / Q000706:statistics & numerical data*; D001499:Bayes Theorem; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D009026:Mortality; D017063:Outcome Assessment, Health Care; D000078202:Systematic Reviews as Topic; D015201:Meta-Analysis as Topic
keywords: Delivery of health care; Health care evaluation mechanisms; Health services research; Hospital admission; Hospitalization; Mortality; Quality of health care; Risk adjustment; Secondary care; Weekend