title: Propensity-matched analysis of association between preoperative anemia and in-hospital mortality in cardiac surgical patients undergoing valvular heart surgeries.
abstract: BACKGROUND
  Anaemia is associated with increased post-operative morbidity and mortality. We retrospectively assess the relationship between preoperative anaemia and in-hospital mortality in valvular cardiac surgical population.
  
  
  METHODS
  Data from consecutive adult patients who underwent valvular repair/ replacement at our institute from January 2010 to April 2014 were collected from hospital records. Anaemia was defined according to WHO criteria (hemoglobin <13g/dl for males and <12g/dl for females). 1:1 matching was done for anemic and non-anemic patients based on propensity for potentially confounding variables. Logistic regression was used to evaluate the relationship between anaemia and in-hospital mortality. MatchIt package for R software was used for propensity matching and SPSS 16.0.0 was used for statistical analysis.
  
  
  RESULTS
  2449 patients undergoing valvular surgery with or without coronary artery grafting were included. Anaemia was present in 37.1% (33.91% among males & 40.88% among females). Unadjusted OR for mortality was 1.6 in anemic group (95% Confidence Interval [95% CI] - 1.041-2.570; p=0.033). 1:1 matching was done on the basis of propensity score for anaemia (866 pairs). Balancing was confirmed using standardized differences. Anaemia had an OR of 1.8 for mortality (95% CI- 1.042 to 3.094, P=0.035). Hematocrit of < 20 on bypass was associated with higher mortality.
  
  
  CONCLUSIONS
  Preoperative anaemia is an independent risk factor associated with in-hospital mortality in patients undergoing valvular heart surgery.
authors.forename: Shreedhar S
authors.initials: SS
authors.lastname: Joshi
authors.affiliation: Department of Anesthesiology, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bengaluru, Karnataka, India.
authors.forename: Antony
authors.initials: A
authors.lastname: George
authors.forename: Dhananjaya
authors.initials: D
authors.lastname: Manasa
authors.forename: Hemalatha M R
authors.initials: HM
authors.lastname: Savita
authors.forename: Prasad T H
authors.initials: PT
authors.lastname: Krishna
authors.forename: A M
authors.initials: AM
authors.lastname: Jagadeesh
mesh_terms: D000328:Adult; D000740:Anemia / Q000150:complications* / Q000401:mortality*; D005260:Female; D006351:Heart Valves / Q000601:surgery*; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D057234:Preoperative Period; D012189:Retrospective Studies; D012306:Risk; D012307:Risk Factors