A multidisciplinary approach to the control of the calcium x phosphate product in dialysis patients

Hyperphosphatemia is common in dialysis patients. With the use of calcium-based phosphate binders and calcitriol, hypercalcemia is also frequently encountered. This combination leads to elevations of the calcium:phosphate product. A product of >2.5 mmol(2)/L-2 (ionized calcium x phosphate [iCa x P]) may increase the risk of periarticular, conjunctival, vascular, and visceral calcifications. A comprehensive multi-disciplinary program was implemented in an effort to control the iCa x P in our dialysis population. This program consisted of an educational package ("A Taste for Life," Abbott Renal Care) delivered by nursing staff; concentrated reviews and advice by dietitians; and reviews, reinforcement, and medication adjustments by nephrologists. The adequacy of the intervention was assessed by comparing baseline iCa x P with that obtained after 3 and 6 months, and by comparing the percentage of patients with iCa x P >2.5 mmol(2)/L-2 before and after the intervention. The program was administered to 112 dialysis patients (43 PD, 69 HD). Baseline iCa was similar for PD and HD patients, but phosphate was significantly lower in PD vs. HD (1.40 +/- 4 vs. 1.84 +/- 0.48 mmol/L; p = 0.0001). Thus, iCa x P was also lower in the PD group (1.78 +/- 54 vs. 2.3 +/- 6; p = 0.0001). Twenty-eight (25%) of patients had iCa x P >2.5 (5 PD, 23 HD). iCa x P fell to 1.69 +/- 0.67 (PD) and 2.06 +/- 0.5 (HD) at 3 months (n = 112) and was 185 +/- 0.5 (PD) and 2.01 +/- 0.5 (HD) at 6 months (n = 102). Repeated measures of ANOVA showed a significant fall in both phosphate (p = 0.014) and iCa x P (p = 0.012) over 6 months for the whole group. Six months after initiation of the program, 13 (13%) of patients had iCa x P >2.5 (chi(2) = 5.18; p = 0.023 cf baseline). Significant improvements in phosphate control-and, thus, iCa x P-were achieved (most notably in HD patients) by this multidisciplinary approach. iCa x P has been adopted as a quality indicator by our program.