title: Pre-operative anaemia is associated with total morbidity burden on days 3 and 5 after cardiac surgery: a cohort study.
abstract: BACKGROUND
  Pre-operative anaemia is associated with mortality and red blood cell (RBC) transfusion requirement after cardiac surgery. However, the effect on post-operative total morbidity burden (TMB) is unknown. We explored the effect of pre-operative anaemia on post-operative TMB.
  
  
  METHODS
  Data were drawn from the Cardiac Post-Operative Morbidity Score (C-POMS) development study (n= 442). C-POMS describes and quantifies (0-13) TMB after cardiac surgery by noting the presence/absence of 13 morbidity domains on days 3 (D3), 5 (D5), 8 (D8) and 15 (D15). Anaemia was defined as a haemoglobin concentration below 130 g/l for men and 120 g/l for women.
  
  
  RESULTS
  Most patients were White British (86.1%) and male (79.2%) and underwent coronary artery bypass surgery (67.4%). Participants with pre-operative anaemia (n= 137, 31.5%) were over three times more likely to receive RBC transfusion (OR 3.08, 95%CI 1.88-5.06,p< 0.001), had greater D3 and D5 TMB (5 vs 3,p< 0.0001; 3 vs 2,p< 0.0001, respectively) and remained in hospital 2 days longer (8 vs 6 days,p< 0.0001) than non-anaemic patients. Transfused patients remained in hospital 5 days longer than non-transfused patients (p< 0.0001), had higher TMB on all days (allp< 0.001) and suffered greater pulmonary, renal, GI, neurological, endocrine and ambulation morbidities (p0.026 to <0.001). Pre-operative anaemia and RBC transfusion were independently associated with increased C-POMS score.
  
  
  CONCLUSIONS
  Pre-operative anaemia and RBC transfusion are independently associated with increased post-operative TMB. Understanding TMB may assist in post-operative patient management to reduce morbidity. We recommend the use of the C-POMS tool as a standard outcome tool in further studies.
authors.affiliation: St Bartholomew's Hospital, Barts Health NHS Trust, London, UK.
authors.forename: Julie
authors.initials: J
authors.lastname: Sanders
authors.affiliation: Centre for Cardiovascular Genetics, University College London, London, UK.
authors.forename: Jackie A
authors.initials: JA
authors.lastname: Cooper
authors.affiliation: Department of Cardiac Anaesthesia and Critical Care, University College London Hospitals NHS Foundation Trust, London, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Farrar
authors.affiliation: UCL Medical School, University College London, London, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Braithwaite
authors.affiliation: UCL Medical School, University College London, London, UK.
authors.forename: Updeshbir
authors.initials: U
authors.lastname: Sandhu
authors.affiliation: University College London Hospitals NHS Trust, London, UK.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Mythen
authors.affiliation: Institute for Sport, Exercise and Health, University College London, 1st Floor 170 Tottenham Court Rd, London, W1T 7HA UK.
authors.forename: Hugh E
authors.initials: HE
authors.lastname: Montgomery
keywords: Anaemia; Cardiac surgery; Post-operative morbidity; Red blood cell transfusion; Total morbidity burden