Assessment of Dietary Phosphorus Intake and Implementation of Parental Phosphate Education in Pediatric Chronic Kidney Disease

Abstract

Introduction: Management of dietary phosphorus intake is a challenge in children with chronic kidney disease and is governed by regional food sources and culinary practices. The aim of this study was to evaluate dietary intake of phosphorus in these children and assess the utility of parental phosphate education for control of hyperphosphatemia. Methods: This prospective study included children aged 2-18 years with CKD stages 2-5D. Phosphorus intake was assessed by 24-hour dietary recall, analyzed using food processor software, and interpreted based on dietary reference intake (DRI) and suggested dietary intake (SDI). Parents of those with hyperphosphatemia were subjected to a structured phosphate education, and serum phosphate was monitored every 2 months for 6 months. Results: Seventy children were recruited (mean age 9.4 ± 3.4 years, CKD5/5D: 51% (n = 36)) with median duration of CKD being 3.8 (IQR2,6) years. In the overall cohort, 50% (35/70) had phosphorus intake exceeding DRI with no significant difference between groups [CKD 5/5D,52.7% (n = 19) vs CKD2-4 47% (n = 16), P = 0.63]. Mean daily phosphorus intake was comparable between children with and without hyperphosphatemia [908 ± 279 mg vs 814 ± 302 mg, P = 0.1]. Based on DRI, 44% of children with normal serum phosphate and 58% with hyperphosphatemia had increased dietary intake of phosphorus (P = 0.15). Based on SDI, 26% with normal serum phosphate and 94% with hyperphosphatemia had increased dietary phosphorus intake (P < 0.001). Hyperphosphatemia was observed in 51% (CKD 2-4); 33% CKD5-5D 66%, P = 0.6). Among 29 children completing 6 months of follow up, there was a significant reduction in mean serum phosphate levels (P = 0.001) which was independent of age, stage of CKD or intake of phosphate binders. At end of the study, hyperphosphatemia persisted in 34%. Conclusion: Compared to DRI, dietary assessment of phosphorus intake based on SDI was significantly associated with hyperphosphatemia in children with CKD 2-5D. In the majority, repeated parental structured phosphate education over 6 months was useful in managing hyperphosphatemia.