title: A multicentre cohort study assessing day of week effect and outcome from emergency appendicectomy.
abstract: BACKGROUND
  There is evidence to suggest that patients undergoing treatment at weekends may be subject to different care processes and outcomes compared with weekdays. This study aimed to determine whether clinical outcomes from weekend appendicectomy are different from those performed on weekdays.
  
  
  METHODS
  Multicentre cohort study during May-June 2012 from 95 centres (89 within the UK). The primary outcome was the 30-day adverse event rate. Multilevel modelling was used to account for clustering within hospitals while adjusting for case mix to produce adjusted ORs and 95% CIs.
  
  
  RESULTS
  When compared with Monday, there were no significant differences for other days of the week considering 30-day adverse events in adjusted models. On Sunday, rates of simple appendicitis were highest, and rates of normal (OR 0.62, 95% CI 0.42 to 0.90) and complex appendicitis (OR 0.65, 95% CI 0.46 to 0.93) lowest. This was accompanied by a 43% lower likelihood in use of laparoscopy on Sunday (OR 0.47, 95% CI 0.32 to 0.69), accompanied by the lowest level of consultant presence for the week. When pooling weekends and weekdays, laparoscopy use remained less likely at the weekend (OR 0.68, 95% CI 0.55 to 0.83), with no significant difference for 30-day adverse event rate (OR 1.01, 95% CI 0.80 to 1.29).
  
  
  CONCLUSIONS
  This study found that weekend appendicectomy was not associated with increased 30-day adverse events. It cannot rule out smaller increases that may be shown by larger studies. It further illustrated that patients operated on at weekends were subject to different care processes, which may expose them to risk.
authors: West Midlands Research Collaborative, Queen Elizabeth Hospital, Birmingham, UK.
authors: Henry J M
authors: HJ
authors: Ferguson
authors: University College London, London, UK.
authors: Nigel J
authors: NJ
authors: Hall
authors: West Midlands Research Collaborative, Queen Elizabeth Hospital, Birmingham, UK.
authors: Aneel
authors: A
authors: Bhangu
mesh_terms: D000293:Adolescent; D000328:Adult; D001062:Appendectomy / Q000009:adverse effects* / Q000706:statistics & numerical data; D015331:Cohort Studies; D004630:Emergencies; D004632:Emergency Medical Services / Q000592:standards / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D016896:Treatment Outcome; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult
keywords: Audit and feedback; Patient safety; Performance measures; Risk management; Surgery