Association of anaemia on heart failure and left ventricular function: A bidirectional Mendelian randomization study

Aims Observational studies have suggested that anaemia is associated with an increased risk of heart failure (HF). But the potential causal association is not clear. We aimed to investigate the association between anaemia and HF risk. Methods and results A Mendelian randomization (MR) analysis was performed to confirm the causal association of anaemia with the risk of HF and left ventricular structure and function. Furthermore, a reverse‐direction MR analyses was conducted to assess the causal effect of HF on anaemia. The MR analysis indicated that genetically predicted anaemia is associated with the increased risk of HF (meta: odd ratio (OR) = 1.12; 95% confidence interval (CI) [1.04, 1.20]; P = 0.002), and left ventricular mass index (β = 1.051; 95% CI [0.384, 1.718]; P = 0.002), left ventricular mass (β = 2.063; 95% CI [0.578, 3.547]; P = 0.006), left atrial minimum volume (β = 0.076; 95% CI [0.008, 0.143]; P = 0.028), and left atrial maximum volume (β = 0.090; 95% CI [0.023, 0.157]; P = 0.009). In the reverse‐direction MR analyses, we found that genetic susceptibility to HF was significantly associated with the increased risk of anaemia (meta: OR = 1.40; 95% CI [1.24, 1.59]; P = 1.79 × 10−7). Conclusions This MR study supports the genetic evidence that there is bidirectional causality between anaemia and the risk of HF as well as anaemia may cause left ventricular hypertrophy and enlargement of the left atrium. Considering the adverse causal effects between the two diseases, more attention should be paid to the prevention and treatment of anaemia in patients with HF.