Daily dietary phosphorus intake variability and hemodialysis patient adherence to phosphate binder therapy.

INTRODUCTION

Phosphate balance could be reached only by an optimized combination of dietary restriction and the careful use of phosphate binders for patients receiving standard hemodialysis treatment. Little is known about individual variability of phosphorus intake and phosphate binder use in hemodialysis patients. The purposes of this study were to quantify phosphorus intake and to describe individual phosphate-binder use in hemodialysis patients.

METHODS

This was a cross-sectional study. The dietary phosphorus intake was assessed using a 3-day duplicate portion sampling method combined with chemical analysis. Patients' adherence to phosphate binders was evaluated by the Morisky Medication Adherence Scale, with a score of <6 being considered as an indicator of inadequate adherence.

FINDINGS

A total of 101 food samples from 36 patients were collected and analyzed. The mean daily phosphorus, protein, and energy intake was 15.1 mg/kg/d, 1.0 g/kg/d, and 28.9 kcal/kg/d, respectively. There was a higher consumption of phosphorus on dialysis days (DDs) than on non-dialysis days (NDDs) (16.2 mg/kg/d vs. 14.0 mg/kg/d, P = 0.035); however, such a trend was not observed for dietary protein and energy intake (1.1 g/kg/d vs. 1.0 g/kg/d, P = 0.706; 30.3 kcal/kg/d vs. 27.6 kcal/kg/d, P = 0.225). A significantly higher percentage of patients on low phosphorus intake (<1000 mg/d) reported inadequate phosphate-binding adherence than those on high phosphorus intake (60% vs. 18%, P = 0.031).

DISCUSSION

Patients receiving hemodialysis had a higher consumption of phosphorus on DDs than on NDDs; such a pattern was not obviously observed for protein and energy intake. For patients achieving phosphorus intake recommendation, medication nonadherence that possibly being attributed to the patient's necessity beliefs may pose extra hurdles for phosphate control.