title: Survival after postoperative morbidity: a longitudinal observational cohort study.
abstract: BACKGROUND
  Previous studies have suggested that there may be long-term harm associated with postoperative complications. Uncertainty exists however, because of the need for risk adjustment and inconsistent definitions of postoperative morbidity.
  
  
  METHODS
  We did a longitudinal observational cohort study of patients undergoing major surgery. Case-mix adjustment was applied and morbidity was recorded using a validated outcome measure. Cox proportional hazards modelling using time-dependent covariates was used to measure the independent relationship between prolonged postoperative morbidity and longer term survival.
  
  
  RESULTS
  Data were analysed for 1362 patients. The median length of stay was 9 days and the median follow-up time was 6.5 yr. Independent of perioperative risk, postoperative neurological morbidity (prevalence 2.9%) was associated with a relative hazard for long-term mortality of 2.00 [P=0.001; 95% confidence interval (CI) 1.32-3.04]. Prolonged postoperative morbidity (prevalence 15.6%) conferred a relative hazard for death in the first 12 months after surgery of 3.51 (P<0.001; 95% CI 2.28-5.42) and for the next 2 yr of 2.44 (P<0.001; 95% CI 1.62-3.65), returning to baseline thereafter.
  
  
  CONCLUSIONS
  Prolonged morbidity after surgery is associated with a risk of premature death for a longer duration than perhaps is commonly thought; however, this risk falls with time. We suggest that prolonged postoperative morbidity measured in this way may be a valid indicator of the quality of surgical healthcare. Our findings reinforce the importance of research and quality improvement initiatives aimed at reducing the duration and severity of postoperative complications.
authors.affiliation: UCL/UCLH Surgical Outcomes Research Centre, Department of Anaesthetics, University College Hospital, London NW1 2BU, UK UCL Centre for Anaesthesia, University College Hospital, London NW1 2BU, UK National Institute for Academic Anaesthesia's Health Services Research Centre, Royal College of Anaesthetists, 35 Red Lion Square, London WC1R 4SG, UK rmoonesinghe@gmail.com.
authors.forename: S R
authors.initials: SR
authors.lastname: Moonesinghe
authors.affiliation: UCL Centre for Anaesthesia, University College Hospital, London NW1 2BU, UK London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
authors.forename: S
authors.initials: S
authors.lastname: Harris
authors.affiliation: UCL/UCLH Surgical Outcomes Research Centre, Department of Anaesthetics, University College Hospital, London NW1 2BU, UK UCL Centre for Anaesthesia, University College Hospital, London NW1 2BU, UK.
authors.forename: M G
authors.initials: MG
authors.lastname: Mythen
authors.affiliation: Intensive Care National Audit & Research Centre, Napier House, 24 High Holborn, London WC1 V 6AZ, UK.
authors.forename: K M
authors.initials: KM
authors.lastname: Rowan
authors.affiliation: UCL/UCLH Surgical Outcomes Research Centre, Department of Anaesthetics, University College Hospital, London NW1 2BU, UK Institute of Sports, Exercise and Health, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: F S
authors.initials: FS
authors.lastname: Haddad
authors.affiliation: UCL/UCLH Surgical Outcomes Research Centre, Department of Anaesthetics, University College Hospital, London NW1 2BU, UK Division of Surgery and Interventional Science, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: M
authors.initials: M
authors.lastname: Emberton
authors.affiliation: UCL/UCLH Surgical Outcomes Research Centre, Department of Anaesthetics, University College Hospital, London NW1 2BU, UK National Institute for Academic Anaesthesia's Health Services Research Centre, Royal College of Anaesthetists, 35 Red Lion Square, London WC1R 4SG, UK Integrative Physiology and Critical Illness Group, University of Southampton, Southampton, UK Anaesthesia and Critical Care Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
authors.forename: M P W
authors.initials: MP
authors.lastname: Grocott
mesh_terms: D000368:Aged; D015331:Cohort Studies; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D053208:Kaplan-Meier Estimate; D007902:Length of Stay / Q000706:statistics & numerical data; D008131:London / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D061213:Mortality, Premature; D011183:Postoperative Complications / Q000401:mortality*; D011184:Postoperative Period; D019984:Quality Indicators, Health Care; D013043:Specialties, Surgical
keywords: complications; complications, morbidity; complications, neurological; surgery, non-cardiac