Osteoprotegerin and mortality in hemodialysis patients with cardiovascular disease

Background: Patients treated with hemodialysis (HD) have an increased mortality, mainly caused by cardiovascular disease (CVD). Osteoprotegerin (OPG) is a glycoprotein involved in the regulation of the vascular calcification process. Previous studies have demonstrated that OPG is a prognostic marker of mortality. The aim of this study was to investigate if OPG was a prognostic marker of all-cause mortality in high-risk patients with end-stage renal disease and CVD. Methods: We prospectively followed 206 HD patients with CVD. OPG was measured at baseline and the patients were followed for 2 years or until reaching the primary endpoint, i.e., all-cause mortality. Results: All-cause mortality during follow-up was 44% (90/206). High OPG was associated with increased mortality, using the first tertile as reference, with an unadjusted HR of 1.70 (CI 1.00 - 2.88) for the second tertile and HR of 1.63 (CI 0.96 - 2.78) for the third tertile. In a multivariate Cox-regression analysis age, CRP and OPG in both the second and third tertile were significantly associated with increased mortality. In the unadjusted survival analysis, a test for trend of OPG yielded a p-value of 0.08; in the adjusted analyses, the p-value for trend was 0.03. Conclusions: In a high-risk population of hemodialysis patients with previously documented cardiovascular disease, a high level of OPG was an independent risk marker of all-cause mortality.