CARE-2 (Calcium Acetate [PhosLo®]/Sevelamer[Renagel®] Evaluation Study 2) for Heart Calcification in Dialysis Patients

Cardiovascular disease is the major cause of death and disability in patients with end-stage renal disease on hemodialysis. It has been hypothesized that ingestion of calcium-based phosphate binders results in net positive calcium balance and vascular calcium deposition. Chertow et al. tested the role of ingested calcium in the progression of cardiovascular calcification in the Treat-To-Goal study (Kidney International 62:245, 2002). They reported that patients treated with calcium-based phosphate binders demonstrated progressive cardiovascular calcification, while patients treated with a calcium-free binder, sevelamer, showed stabilization or improvement in calcification scores. However, the protocol did not prohibit intake of supplemental oral calcium in the sevelamer group, which confounded their ability to accurately test the calcium hypothesis. Moreover, due to the cholesterol sequestering activities of sevelamer, the low-density lipoprotein (LDL) cholesterol was lower among sevelamer-treated patients than the calcium treated patients, resulting in a major imbalance in a cardiovascular risk factor. Lowering LDL level reduces progression of CVC and therefore confounds interpretation of the study. Subsequently, it has been reported in the lay press that patients randomized to sevelamer or calcium-based binders in the Dialysis Clinical Outcomes Revisited (DCOR) study have failed to show a difference in mortality or major secondary endpoints (Suki et al., To be presented American Society of Nephrology November 2005). To circumvent these limitations, the CARE-2 study will test the hypothesis that if LDL levels are lowered to a similar level in calcium acetate and sevelamer-treated patients, there will be no difference in the progression of cardiac calcification. CARE-2 will randomize patients with elevated LDL to calcium acetate or sevelamer. Atorvastatin is added to achieve LDL \< 70 mg/dL in both treatment groups. The primary endpoint is change in cardiac calcification scores, determined by electron beam scanning after 1 year. Secondary endpoints include the ability of calcium acetate and sevelamer to control phosphorus and meet NKF-K/DOQI guidelines.