Circulating Aminoterminal Propeptide of Type III Procollagen as a Biomarker of Cardiovascular Events in Patients Undergoing Hemodialysis

Aim: Type III collagen abundantly exists in the cardiovascular system, including the aorta and heart. We prospectively investigated whether serum levels of aminoterminal propeptide of Type III procollagen (PIIINP), a circulating biomarker of cardiovascular fibrosis, could predict cardiovascular events in patients undergoing hemodialysis. Methods: Serum PIIINP concentrations were measured in 244 patients undergoing maintenance hemodialysis (men, 126; women, 118; mean age, 64 +/- 11 years; dialysis duration, 11.5 +/- 7.8 years) by immunoradiometric assay in February 2005. The endpoint was cardiovascular events, and the patients were followed up until the endpoint was reached, or until January 31, 2011. Results: During the follow-up for 4.7 +/- 1.8 years, cardiovascular events occurred in 78 (30.3%) of 244 patients. Stepwise Cox hazard analysis revealed that cardiovascular events were associated with increased serum PIIINP concentration (1 U/mL; hazard ratio, 1.616; P = 0.0001). The median serum PIIINP concentrations were higher in patients with cardiovascular events than in those without (2.30 +/- 0.19 U/mL vs 1.30 +/- 0.03 U/mL; P<0.0001). When the patients were assigned to subgroups based on serum PIIINP cut-off value for cardiovascular events of 1.75 U/mL, defined by receiver operating characteristic analysis, cardiovascular event-free survival rates at 5 years were lower (P = 0.0001) in the subgroup of serum PIIINP >= 1.75 U/mL than in that of serum PIIINP < 1.75 U/mL (31.9% vs 88.2%). Conclusions: Serum PIIINP could be a new biomarker for predicting the cardiovascular events in patients undergoing hemodialysis.