However, previous studies have shown that the HAS-BLED score may underestimate the bleeding risk (Caldeira et al., 2014; Senoo et al., 2016), which was also suggested by our research with the findings that some risk factors that not mentioned in HAS-BLED (like hypothyroidism, cancer, combining P-gp substrate or hormones or SSRIs or acetaminophen, and low body weights) need to be considered. This evidence concerns the gene PGP and cancer.