title: Variation in the risk of venous thromboembolism following colectomy.
abstract: BACKGROUND
  Guidelines recommend extended thromboprophylaxis following colectomy for malignant disease, but not for non-malignant disease. The aim of this study was to determine absolute and relative rates of venous thromboembolism (VTE) following colectomy by indication, admission type and time after surgery.
  
  
  METHODS
  A cohort study of patients undergoing colectomy in England was undertaken using linked primary (Clinical Practice Research Datalink) and secondary (Hospital Episode Statistics) care data (2001-2011). Crude rates and adjusted hazard ratios (HRs) were calculated for the risk of first VTE following colectomy using Cox regression analysis.
  
  
  RESULTS
  Some 12,388 patients were identified; 312 (2·5 per cent) developed VTE after surgery, giving a rate of 29·59 (95 per cent c.i. 26·48 to 33·06) per 1000 person-years in the first year after surgery. Overall rates were 2·2-fold higher (adjusted HR 2·23, 95 per cent c.i. 1·76 to 2·50) for emergency compared with elective admissions (39·44 versus 25·78 per 1000 person-years respectively). Rates of VTE were 2·8-fold higher in patients with malignant disease versus those with non-malignant disease (adjusted HR 2·84, 2·04 to 3·94). The rate of VTE was highest in the first month after emergency surgery, and declined from 121·68 per 1000 person-years in the first month to 25·65 per 1000 person-years during the rest of the follow-up interval. Crude rates of VTE were similar for malignant and non-malignant disease (114·76 versus 120·98 per 1000 person-years respectively) during the first month after emergency surgery.
  
  
  CONCLUSIONS
  Patients undergoing emergency colectomy for non-malignant disease have a similar risk of VTE as patients with malignant disease in the first month after surgery.
authors.affiliation: Division of Epidemiology and Public Health, School of Medicine, University of Nottingham, Nottingham, UK.|National Institute for Health Research Nottingham Digestive Disease Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Humes
authors.affiliation: Division of Epidemiology and Public Health, School of Medicine, University of Nottingham, Nottingham, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Walker
authors.affiliation: Division of Epidemiology and Public Health, School of Medicine, University of Nottingham, Nottingham, UK.
authors.forename: J
authors.initials: J
authors.lastname: Blackwell
authors.affiliation: Thrombosis and Haemophilia Centre, Guy's and St Thomas' NHS Foundation Trust, St Thomas' Hospital, London, UK.
authors.forename: B J
authors.initials: BJ
authors.lastname: Hunt
authors.affiliation: Division of Epidemiology and Public Health, School of Medicine, University of Nottingham, Nottingham, UK.
authors.forename: J
authors.initials: J
authors.lastname: West
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003082:Colectomy / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology* / Q000209:etiology; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D006113:United Kingdom / Q000453:epidemiology; D054556:Venous Thromboembolism / Q000453:epidemiology* / Q000209:etiology