Dietary intervention focused on phosphate intake in hemodialysis patients with hyperphosphatemia

Background: Elevated serum phosphorus has been identified as a cardiovascular risk factor. This study aimed to assess the effectiveness of dietary intervention to reduce phosphorus intake and to improve the calcium-phosphorus metabolism in hemodialysis patients. Design: Patients were included in a 6-month, 2-group experimental study if their previous 3-month average serum phosphorus was over 5.5 mg/dl. Patients were allocated to intensive dietary intervention or usual dietary recommendations. The clinical end-points were the multivariate-adjusted change in serum phosphorus and the number of patients who achieved serum phosphorus levels of < 5.5 mg/dl and serum phosphorus levels of < 5 mg/dl. Results: 80 dialysis patients completed the study, 41 in the experimental group and 39 in the control group. After 6 months, phosphorus intake (702 +/- 168 vs. 872 +/- 242 mg/24 h; p = 0.002) was lower in the experimental group than in the control group, with no inter-group differences in protein-caloric intake. Serum phosphorus decreased 1.67 mg/dl in the experimental group and 0.58 mg/dl in the control group (multivariate-adjusted difference 0.93 mg/dl; 95% CI 0.34 - 1.52; p = 0.003). Serum phosphorus < 5.5 mg/dl and serum phosphorus < 5 mg/dl were attained more frequently in the experimental group (51 vs. 18%, p = 0.002 and 31.7 vs. 15.4%, p = 0.08 respectively). Conclusions: Intensive dietary intervention focusing on phosphorus intake may be useful to reduce phosphorus retention and to improve calcium-phosphorus metabolism in hemodialysis patients.