TNFRSF11B and peripheral arterial disease: Giovannini et al. [73], in a retrospective observational study that analyzed OPG levels in 1393 diabetic patients with and without PAD, demonstrated that OPG levels were significantly higher in PAD vs. non-PAD patients (6.54 ± 7.76 pmol/L vs. 2.98 ± 2.01 pmol/L) and that OPG levels also correlated positively with the clinical severity of PAD.