CINACALCET BUT NOT VITAMIN D USE MODULATES THE SURVIVAL BENEFIT ASSOCIATED WITH SEVELAMER IN THE INDEPENDENT STUDY

INTRODUCTION AND AIMS: Whether the concomitant use of calcium sensing modulator or vitamin D with either a calcium free or calcium containing phosphate binder impacts patient-centered outcomes remains to be elucidated METHODS: Post hoc analysis of an open label, randomized, controlled trial designed to evaluate the impact of sevelamer (SV) vs calcium salts (CS) on survival in incident dialysis patients. All individuals were followed until study completion or death. Cinacalcet and vitamin D were administered to a portion of patients as part of routine care (53% and 42%, respectively). We tested the impact of cinacalcet and vitamin D on survival for the overall study cohort and in both treatment arms of the original study. RESULTS: We recruited 466 middle-age (65 years) men and women. After a mean follow-up of 28(10) months, SV but not cinacalcet administration was associated with a survival benefit. However, a significant (p=0.003) interaction of phosphate binder and cinacalcet use on mortality was observed (Figure 1). A synergistic survival benefit was noted between SV and cinacalcet (HR 0.41, 95%CI 0.17-1.01, p=0.054 for SV treated subjects receiving vs not receiving cincalcet). In contrast a trend toward an increased mortality was observed for patients receiving CS and cinacalcet concomitantly (HR 1.5, 95%CI 0.96-2.34; p=0.07 for CS treated subjects receiving vs not receiving cincalcet). No effect on mortality or interaction with phosphate binder use was noted with vitamin D. CONCLUSIONS: Though hypothesis generating, these results lend support to a hypothesis that use of a calcium-free vs -containing phosphate binder may increase survival in incident hemodialysis patients, in particular, when patient are treated concurrently with cinacalcet.