Osteoprotegerin (OPG) is a marker and regulator of arterial calcification, and it is related to survival in hemodialysis patients. The link between OPG and aortic stiffening - a consequence of arterial calcification - has not previously been evaluated in this population, and it is not known whether OPG related mortality risk is mediated by arterial stiffening.

At baseline OPG and aortic pulse wave velocity (PWV) was measured in 98 hemodialysis patients who were then followed for a median of 18 months. The relationship between OPG and PWV was assessed by multivariate linear regression. The role of PWV in mediating OPG related mortality risk was evaluated by including both OPG and PWV in the same survival model.

At baseline mean (SD) PWV was 11.2 (3,3) m/s and median OPG (interquartile range) was 11.1 (7.5–15.9) nmol/L. There was a strong positive linear relationship between PWV and lnOPG (beta=1.48, p=0.009), independent of other covariates. During follow-up 28 patients died (mortality rate 18.4/100 patient years). In separate survival models both PWV and lnOPG were related to all cause mortality (hazard ratios 1.21[1.07–1.38] and 5.39 [2.16–13.43], respectively). When both PWV and lnOPG were entered into the same model, only OPG remained significantly associated with mortality (hazard ratios 1.12 [0.97–1.28] and 4.37 [1.62–11.80], respectively).

In hemodialysis patients OPG is strongly related to PWV and OPG related mortality risk may, in part, mediated by increased PWV.