TNFRSF11B and peripheral arterial disease: Moreover serum levels of pro-inflammatory cytokines were significantly higher in diabetic PAD patients having CLI than in those with stable PAD (HMGB-1 8.35 ± 12.72 ng/mL vs 4.53 ± 7.65 ng/mL, P < 0.001; OPG 7.64 ± 9.29 pmol/L vs 3.24 ± 2.56 pmol/L, P < 0.001; HsCRP 18.1 ± 15.9 mg/L vs 9.3 ± 5.1 mg/L, P < 0.001; IL-6 62.1 ± 29.4 pg/mL vs 41.5 ± 18.7 pg/mL, P < 0.001) (Fig. 2).