Conversely, plasma concentrations of 3 proteins were higher in patients with PAD compared to those without PAD: Alpha 1-microglobulin (16.54 [SD 7.50] vs. 14.86 [SD 6.62], GDF15 (1632.29 [SD 1252.85] vs. 1164.69 [SD 794.99] pg/mL, p < 0.001), and endostatin (7.51 [SD 5.22] vs. 5.22 [SD 3.01] pg/mL, p = 0.044) (Table 2). Here, COL18A1 is linked to peripheral arterial disease.