Cinacalcet Plus Low-Dose Vitamin D May Slow CAC Progressionsecondary hyperparathyroidism (SHPT) and attenuate progression of coronary artery calcification (CAC) compared with flexible vitamin D therapy alone in hemodialysis (HD) patients, according to a new study presented here at the National Kidney Foundation's 2010 Spring Clinical Meetings.
It is well documented that CAC is common and progressive in HD patients. Researchers theorize that CAC may be aggravated by elevated plasma parathyroid hormone (PTH) and/or calcium (Ca) and phosphorus (P) levels.
In the new study, researchers randomized 360 HD patients with SHPT and detectable CAC to treatment with cinacalcet (30-180 mg a day) plus low-dose vitamin D or to flexible vitamin D therapy. In both arms of the study, Ca-based phosphate binders were used exclusively and the therapeutic target for PTH was 150-300 pg/mL. The primary end point of the study was the percent change in Agatston CAC score from baseline to week 52. Additional analyses were also conducted using the volume score, and the investigators analyzed the change in Agatston calcium score for the aorta.
It was observed that Agatston CAC scores increased by 31% from baseline in the flexible vitamin D group and by 24% in the cinacalcet group. The volume CAC scores increased by 30% from baseline in the flexible vitamin D group but only by 22% in the cinacalcet group, and the Agatston aorta scores increased by 33% in the flexible vitamin D group but only 20% in the cinacalcet group.
The investigators reported that the median plasma PTH levels decreased by 65 pg/mL from baseline at week 52 in the flexible vitamin D group and by 132 pg/mL in the cinacalcet group. The mean serum Ca increased by 0.17 mg/dL in the flexible vitamin D group but decreased by 0.51 mg/dL in the cinacalcet group and the serum P decreased by 0.24 mg/dL in the flexible vitamin D group and by 0.92 mg/dL in the cinacalcet group.