ABSTRACT: Background The underlying mechanisms of arterial stiffness remain not fully understood. This study aimed to identify a urinary proteomic profile to illuminate its pathogenesis and to determine the prognostic value of the profile for adverse outcomes. Methods and Results We measured aortic stiffness using pulse wave velocity (PWV) and analyzed urinary proteome using capillary electrophoresis coupled with mass spectrometry in 669 randomly recruited Flemish patients (mean age, 50.2 years; 51.1% women). We developed a PWV-derived urinary proteomic score (PWV-UP) by modeling PWV with proteomics data at baseline through orthogonal projections to latent structures. PWV-UP that consisted of 2336 peptides explained the 65% variance of PWV, higher than 36% explained by clinical risk factors. PWV-UP was significantly associated with PWV (adjusted β=0.73 [95% CI, 0.67-0.79]; P<0.0001). Over 9.2 years (median), 36 participants died, and 75 experienced cardiovascular events. The adjusted hazard ratios (+1 SD) were 1.46 (95% CI, 1.08-1.97) for all-cause mortality, 2.04 (95% CI, 1.07-3.87) for cardiovascular mortality, and 1.39 (95% CI, 1.11-1.74) for cardiovascular events (P≤0.031). For PWV, the corresponding estimates were 1.25 (95% CI, 0.97-1.60), 1.35 (95% CI, 0.85-2.15), and 1.22 (95% CI, 1.02-1.47), respectively (P≥0.033). Pathway analysis revealed that the peptides in PWV-UP mostly involved multiple pathways, including collagen turnover, cell adhesion, inflammation, and lipid metabolism. Conclusions PWV-UP was highly associated with PWV and could be used as a biomarker of arterial stiffness. PWV-UP, but not PWV, was associated with all-cause mortality and cardiovascular mortality, implying that PWV-UP-associated peptides may be multifaceted and involved in diverse pathological processes beyond arterial stiffness.
