Association of 25‐hydroxyvitamin D with anemia risk in patients scheduled for cardiac surgery

Summary Introduction There is emerging data that vitamin D plays a role in erythropoiesis. Low 25‐hydroxyvitamin D (25 OHD ) levels may therefore be a risk factor for anemia in patients scheduled for cardiac surgery. Methods We investigated 4428 consecutive cardiac surgical patients to determine an association between anemia (hemoglobin concentration <12.5 g/dL, 27.1% of the study cohort) and circulating 25 OHD . Results In patients with severe vitamin D deficiency (25 OHD  < 12.5 n m ), mean hemoglobin concentrations were 0.80 g/dL lower compared with patients with adequate 25 OHD levels (50.0–100 n m ). Hemoglobin levels were not significantly different at 25 OHD levels above 100 n m compared with 50.0–100 n m . In multivariable‐adjusted logistic regression analyses, the odds ratios for anemia of the groups with severe and moderate vitamin D deficiency (12.5–29.9 n m ) were 1.70 (95% CI :1.09–2.63) and 1.41 (95% CI :1.02–1.96), respectively, compared with patients who had circulating 25 OHD levels of 75–100 n m . Prevalence of deficient circulating 25 OHD levels was highest in anemia of chronic kidney disease. Conclusion This cross‐sectional study demonstrates an independent association between vitamin D status and anemia risk with optimal 25 OHD levels of 75–100 n m . Randomized controlled trials are needed to clarify whether this association is causal.