- \(\textbf {Background:}\)
Preoperative anemia is considered an independent risk factor of poor clinical outcome in cardiac surgical patients. Low vitamin D status may increase anemia risk.
\(\textbf {Methods:}\)
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 \((1,25[OH]_{2}D)\).
\(\textbf {Results:}\)
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 \(1,25(OH)_{2}D\), mean Hb concentrations were 1.2 g/dL lower in the lowest \(1,25(OH)_{2}D\) category (<40 pmol/l) than in the highest \(1,25(OH)_{2}D\) 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 \(1,25(OH)_{2}D\) 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 \(1,25(OH)_{2}D\) values in the highest category, respectively. Anemia risk was greatest in patients with dual deficiency of 25OHD and \(1,25(OH)_{2}D\) (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 \(1,25(OH)_{2}D\)levels were most frequent in anemia of chronic kidney disease.
\(textbf {Conclusion:}\)
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.