Effect of a dietitian-managed bone algorithm on serum phosphorus level in maintenance hemodialysis patients

This study examined the effectiveness of a registered dietitian (RD)-managed bone metabolism algorithm compared with a non-RD (registered nurse and the nephrologist)-managed one on serum phosphorus (PO4) and related clinical outcomes (corrected serum calcium [cCa] level, intact parathyroid hormone [iPTH] level, incidence of parathyroidectomy) among in-center maintenance hemodialysis (MHD) patients.

The study was an 18-month retrospective review of adult MHD patients (n = 252) at 5 outpatient dialysis centers in western Massachusetts and Connecticut before and after change in the management of a comprehensive bone metabolism treatment algorithm (intravenous vitamin D, phosphate-binding medication, calcimimetic) from non-RD to RD. Calendar-matched timepoints representing 3-month averages during the non-RD- and RD-managed periods of the same algorithm were used for analyses. Comparisons of outcomes at non-RD-managed timepoint 2 (February 2009-April 2009) and RD-managed timepoint 6 (February 2010-April 2010) were performed considering potential demographic and clinical confounders.

On average, serum PO4 level was lower during the RD-managed timepoint 6 (5.17 ± 1.23 mg/dL; mean ± standard deviation) compared with non-RD-managed timepoint 2 (5.23 ± 1.24 mg/dL), although the difference between these calendar-matched timepoints was not statistically significant (F = .108, P = .74) after controlling for age, dietary intake (equilibrated normalized protein catabolic rate), and dialysis adequacy (equilibrated Kdrt/V). Mean cCa at RD-managed timepoint 6 (8.76 ± 0.65 mg/dL) was not significantly different from non-RD-managed timepoint 2 (8.79 ± 0.74), and the difference between serum iPTH level at timepoint 6 (363.0 ± 296.8 pg/mL) compared with timepoint 2 (319.8 ± 251.5 pg/mL) was nonsignificant (F = .650, P = .42) after controlling for age. There were fewer parathyroidectomies during the RD-managed period (0.8%) compared with the non-RD-managed period (1.6%).

RDs may be equally effective as non-RDs in bone metabolism algorithm management with respect to serum PO4, cCa, and iPTH control in MHD patients. Further research is needed to prospectively evaluate the effect of RD management on these bone mineral outcomes.