Although PAD is a well-known complication in diabetes, the possibility of a false-negative diagnosis of PAD has been reported in patients with diabetes when diagnosed with the ABI result.[28] In the present study, serum OPG and TRAIL levels were regulated or tended to be regulated in PAD and diabetes, respectively (Fig. 1A and B). The gene discussed is TNFRSF11B; the disease is peripheral arterial disease.