Treatment of hyperphosphatemia in hemodialysis patients: The Calcium Acetate Renagel Evaluation (CARE Study)

Abstract

Background: Hyperphosphatemia underlies development of hyperparathyroidism, osteodystrophy, extraosseous calcification, and is associated with increased mortality in hemodialysis patients.

Methods: To determine whether calcium acetate or sevelamer hydrochloride best achieves recently recommended treatment goals of phosphorus </=5.5 mg/dL and Ca x P product </=55 mg(2)/dL(2), we conducted an 8-week randomized, double-blind study in 100 hemodialysis patients.

Results: Comparisons of time-averaged concentrations (weeks 1 to 8) demonstrated that calcium acetate recipients had lower serum phosphorus (1.08 mg/dL difference, P= 0.0006), higher serum calcium (0.63 mg/dL difference, P < 0.0001), and lower Ca x P (6.1 mg(2)/dL(2) difference, P= 0.022) than sevelamer recipients. At each week, calcium acetate recipients were 20% to 24% more likely to attain goal phosphorus [odds ratio (OR) 2.37, 95% CI 1.28-4.37, P= 0.0058], and 15% to 20% more likely to attain goal Ca x P (OR 2.16, 95% CI 1.20-3.86, P= 0.0097). Transient hypercalcemia occurred in 8 of 48 (16.7%) calcium acetate recipients, all of whom received concomitant intravenous vitamin D. By regression analysis hypercalcemia was more likely with calcium acetate (OR 6.1, 95% CI 2.8-13.3, P < 0.0001). Week 8 intact PTH levels were not significantly different. Serum bicarbonate levels were significantly lower with sevelamer hydrochloride treatment (P < 0.0001).

Conclusion: Calcium acetate controls serum phosphorus and calcium-phosphate product more effectively than sevelamer hydrochloride. Cost-benefit analysis indicates that in the absence of hypercalcemia, calcium acetate should remain the treatment of choice for hyperphosphatemia in hemodialysis patients.