Effect of day of the week on short- and long-term mortality after emergency general surgery.
BACKGROUND
The effect of day of the week on outcome after surgery is the subject of debate. The aim was to determine whether day of the week of emergency general surgery alters short- and long-term mortality.


METHODS
This was an observational study of all patients undergoing emergency general surgery in Scotland between 1 January 2005 and 31 December 2007, followed to 2012. Multilevel logistic and Cox proportional hazards regression were used to assess the effect of day of the week of surgery on outcome after adjustment for case mix and risk factors. The primary outcome was perioperative mortality; the secondary outcome was overall survival.


RESULTS
A total of 50 844 patients were identified, of whom 31 499 had an emergency procedure on Monday to Thursday and 19 345 on Friday to Sunday. Patients undergoing surgery at the weekend were younger (mean 45·9 versus 47·5 years; P < 0·001) and had fewer co-morbidities, but underwent riskier and/or more complex procedures (P < 0·001). Patients who had surgery at the weekend were more likely to have been operated on sooner than those who had weekday surgery (mean time from admission to operation 1·2 versus 1·6 days; P < 0·001). No difference in perioperative mortality (odds ratio 1·00, 95 per cent c.i. 0·89 to 1·13; P = 0·989) or overall survival (hazard ratio 1·01, 0·97 to 1·06; P = 0·583) was observed when surgery was performed at the weekend. There was no difference in overall survival after surgery undertaken on any particular day compared with Wednesday; a borderline reduction in perioperative mortality was seen on Tuesday.


CONCLUSIONS
There was no difference in short- or long-term mortality following emergency general surgery at the weekend, compared with mid-week.
Department of Anaesthesia, Critical Care and Pain Medicine, Royal Infirmary of Edinburgh, Edinburgh, UK.|Surgical and Perioperative Health Research (SPHeRe), University of Edinburgh, Edinburgh, UK.
M A
MA
Gillies
Centre for Population and Health Sciences, University of Edinburgh, Edinburgh, UK.
N I
NI
Lone
Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK.
R M
RM
Pearse
Information Services Division, NHS Services Scotland, South Gyle, Edinburgh, UK.
C
C
Haddow
Information Services Division, NHS Services Scotland, South Gyle, Edinburgh, UK.
L
L
Smyth
Clinical Surgery, University of Edinburgh, Royal Infirmary of Edinburgh, Edinburgh, UK.
R W
RW
Parks
Department of Anaesthesia, Critical Care and Pain Medicine, Royal Infirmary of Edinburgh, Edinburgh, UK.
T S
TS
Walsh
Surgical and Perioperative Health Research (SPHeRe), University of Edinburgh, Edinburgh, UK.|Clinical Surgery, University of Edinburgh, Royal Infirmary of Edinburgh, Edinburgh, UK.
E M
EM
Harrison
D004636:Emergency Service, Hospital / Q000592:standards*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012307:Risk Factors; D012606:Scotland; D013514:Surgical Procedures, Operative / Q000401:mortality*; D013997:Time Factors; D016896:Treatment Outcome