Dietary phosphorus intake and distribution in Chinese peritoneal dialysis patients with and without hyperphosphatemia.

BACKGROUND: The present study was conducted to analyze the dietary phosphorus intake and distribution in different food categories in peritoneal dialysis (PD) patients, to evaluate the relationship between dietary phosphorus intake and hyperphosphatemia.
METHODS: It was a cross-sectional study, in which prevalent Chinese PD patients were instructed by dietitians to record 3-day diet diary. Dietary phosphorus and other nutrient contents were calculated using a food composition computer program. Renal and peritoneal phosphorus clearance (CPh) was estimated, and serum phosphorus, as well as other serological parameters, were measured at the same time.
RESULTS: 93 PD patients [age 52.9 ± 13.0 years, PD duration 30.1 (8.0, 71.0) months] finished the 3-day diet diary. Hyperphosphatemic patients (serum phosphorus level 1.97 ± 0.28 mmol/l, n = 48) showed higher dietary phosphorus intake (771.6 ± 195.1 versus 620.8 ± 155.3 mg/day, p = 0.040) than those with normal serum phosphorus level (1.37 ± 0.21 mmol/l, n = 45), due to greater phosphorus intake from meat, snacks, beverage, food condiments and additives. Significantly lower dietary phosphorus intake (605.6 ± 122.5 mg/day) and phosphorus to protein ratio (12.7 ± 1.4 mg/g) were observed in patients with anuria who maintained serum phosphorus within normal range. Multivariate linear regression analysis indicated normalized phosphorus intake, renal CPh and dietary protein intake were independently associated with serum phosphorus level.
CONCLUSION: High dietary phosphorus intake is associated with elevated serum phosphorus level in PD patients. The study suggests that PD patients, particularly those with anuria, shall limit the intake of meat, snacks, beverage, food condiments and additives to reduce dietary phosphorus ingestion.