Randomized Trial of Acute Changes in Plasma Phosphate After Phosphorus-Standardized Meals in Peritoneal Dialysis

Abstract

Introduction Hyperphosphatemia is associated with increased morbidity and mortality in patients with chronic kidney disease. The aim of this study was to assess whether a meal with high phosphorus content would affect plasma phosphate in the hours that follow among subjects with end-stage kidney disease on peritoneal dialysis. Methods This was a single-blinded randomized cross-over trial of 12 subjects on maintenance peritoneal dialysis, in which subjects were randomized to consume a meal with either high or low phosphorus content on 2 separate trial days. On each trial day, plasma phosphate was measured immediately before consumption of the standardized meal and after 1, 2, 3, and 5 hours. Results The mean fasting plasma phosphate at baseline was 1.69 ± 0.22 mmol/l. Plasma phosphate was similar between the 2 meals at baseline, as well as at 1, 2, 3, and 5 hours after consumption. The largest observed difference in plasma phosphate between the 2 meals was 0.15 mmol/l, which occurred 5 hours after consumption (high-phosphorus meal 1.75 ± 0.32 mmol/l vs. low-phosphorus meal 1.60 ± 0.14 mmol/l ( P = 0.06)). Using summary analyses for repeated measures, we observed a significant difference in the plasma phosphate between the 2 meals ( P = 0.03). Conclusion Our results show that in subjects with end-stage kidney disease, a meal with high phosphorus content has only a negligible effect on plasma phosphate compared to a meal with low phosphorus content. Thus, large increases in plasma phosphate cannot be accounted for by a high intake of phosphorus in the hours before blood sampling.

The effect of dietary phosphorus load and food matrix on postprandial serum phosphate in hemodialysis patients: a pilot study

“…In a recent study by Lundin et al . in 12 HD patients, a meal with high phosphorus content did not significantly affect plasma phosphate compared to a meal with low phosphorus content 47 . Isakova et al .…”

“…There are a limited number of small studies in this field. In a recent study by Lundin et al in 12 HD patients, a meal with high phosphorus content did not significantly affect plasma phosphate compared to a meal with low phosphorus content 47 . Isakova et al examined the difference between 2 whole-food meals of 250 mg and 500 mg of phosphorus content in 13 patients with CKD stage 3 to 4, and observed that serum phosphate decreased after both meals.…”

“…The timing of the intervention may have greater than previous appreciated effect on the serum phosphate levels. The first three studies which were negative were conducted in the morning 22,47,49 . The study by Brown et al was conducted in the morning and failed to show results with solid foods but did lead to an increase in serum phosphate with a large dose of a phosphate supplement 23 .…”

“…The timing of the intervention may have greater than previous appreciated effect on the serum phosphate levels. The first three studies which were negative were conducted in the morning 22 , 47 , 49 . The study by Brown et al .…”

A 6-Month clinical practice pilot study of sucroferric oxyhydroxide on nutritional status in patients on peritoneal dialysis

“…We recognize that phosphorus levels may change before or after meals. However, a recent study found that a high phosphorus meal only has a negligible effect on plasma phosphate compared to low phosphorus meal in PD patients [ 22 ]. Additionally, we did not have information on D/P creatinine ratio at baseline and end of study in all participants.…”