title: Independent association of circulating vitamin D metabolites with anemia risk in patients scheduled for cardiac surgery.
abstract: BACKGROUND
  Preoperative anemia is considered an independent risk factor of poor clinical outcome in cardiac surgical patients. Low vitamin D status may increase anemia risk.
  
  
  METHODS
  We investigated 3,615 consecutive patients scheduled for cardiac surgery to determine the association between preoperative anemia (hemoglobin [Hb] <12.5 g/dL) and circulating levels of the vitamin D metabolites 25-hydroxyvitamin D (25OHD) and 1,25-dihydroxyvitamin D (1,25[OH]2D).
  
  
  RESULTS
  Of the study cohort, 27.8 % met the criteria for anemia. In patients with deficient 25OHD levels (<30 nmol/l) mean Hb concentrations were 0.5 g/dL lower than in patients with adequate 25OHD levels (50.0-125 nmol/l; P<0.001). Regarding 1,25(OH)2D, mean Hb concentrations were 1.2 g/dL lower in the lowest 1,25(OH)2D category (<40 pmol/l) than in the highest 1,25(OH)2D category (>70 pmol/l; P<0.001). In multivariable-adjusted logistic regression analyses, the odds ratios for anemia of the lowest categories of 25OHD and 1,25(OH)2D were 1.48 (95%CI:1.19-1.83) and 2.35 (95%CI:1.86-2.97), compared with patients who had adequate 25OHD levels and 1,25(OH)2D values in the highest category, respectively. Anemia risk was greatest in patients with dual deficiency of 25OHD and 1,25(OH)2D (multivariable-adjusted OR = 3.60 (95%CI:2.40-5.40). Prevalence of deficient 25OHD levels was highest in anemia of nutrient deficiency, whereas low 1,25(OH)2D levels were most frequent in anemia of chronic kidney disease.
  
  
  CONCLUSIONS
  This cross-sectional study demonstrates an independent inverse association between vitamin D status and anemia risk. If confirmed in clinical trials, preoperative administration of vitamin D or activated vitamin D (in case of chronic kidney disease) would be a promising strategy to prevent anemia in patients scheduled for cardiac surgery.
authors.affiliation: Clinic for Thoracic and Cardiovascular Surgery Heart and Diabetes Center North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany.
authors.forename: Jana B
authors.initials: JB
authors.lastname: Ernst
authors.affiliation: Clinic for Thoracic and Cardiovascular Surgery Heart and Diabetes Center North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Becker
authors.affiliation: Institute for Laboratory and Transfusion Medicine, Heart and Diabetes Center North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Kuhn
authors.affiliation: Clinic for Thoracic and Cardiovascular Surgery Heart and Diabetes Center North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany.
authors.forename: Jan F
authors.initials: JF
authors.lastname: Gummert
authors.affiliation: Clinic for Thoracic and Cardiovascular Surgery Heart and Diabetes Center North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany.
authors.forename: Armin
authors.initials: A
authors.lastname: Zittermann
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000453:epidemiology* / Q000378:metabolism; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019616:Thoracic Surgical Procedures; D014807:Vitamin D / Q000378:metabolism*
chemical_list: D014807:Vitamin D