In the first model, when adjusted for BMI tertiles, serum UA tertiles, albumin tertiles, GGT tertiles, the presence of hypertension, atrial fibrillation, and anemia, the odds ratio conferred by log 25(OH)D in the lower tertile was 4.02 (1.05–15.42, 95% CI), and log 25(OH)D remained a significant independent determinant of HFrEF (p = 0.027) (Model C). Here, ALB is linked to anemia (phenotype).