FO046MULTICENTRE RANDOMIZED CONTROL Trial OF PHOSPHATE CONTROL WITH A MODIFIED AS COMPARED TO STANDARD RENAL DIET.

Abstract

Introduction and Aims: Dietary Phosphorous (P) restriction is acritical component of phosphate control in patients with kidney failure. The standard renal diet (approx. 1000mg P/day) is limited and is often associated with poor compliance. A modified renal diet, including the increased use of pulses, nuts and whole grains (which contain phytate bound P with a low bioavailability), along with an increased focus on avoiding foods with P additives) may offer improved or similar P levels as the standard renal diet but with a wider food choice. Methods: We conducted a national, multicentre, pragmatic, parallel arm, open label, randomized control trial (1:1 allocation ratio) of 1 month of modified vs. standard diet in 74 prevalent anuric adults on maintenance haemodialysis for more than 3 months with a3‐month mean pre‐dialysis serum phosphate ([P]) >1.6mmol/L and a stable phosphate binder prescription. Subjects with a history of pre‐dialysis [K] >6.0 mmol/L, parathyroidectomy or recent concurrent illness were excluded. Subjects were reviewed by a clinical renal dietician who either reviewed the standard diet with them or educated them in the modified diet. Analysis was on a modified intention‐to‐treat basis of the difference between diets in Follow‐up [P] minus Baseline [P] using an inde‐pendent sample t test and a 2 sided type 1 error rate of 0.05. Results: Seventy‐four subjects were recruited from 13 university affiliated dialysis units (median recruitment: 5 subjects per site). Two patients did not have a follow‐up pre‐dialysis [P], (1 had an insufficient sample for analysis and 1 received a renal transplant during the study period), and were thus excluded from the analysis. The study population was 96% Caucasian, 69% male, 36% of subjects had diabetes. The modified diet was well tolerated, with good compliance. Baseline and follow‐up [P] in Modified Diet arm was 2.1 (0.5) and 2.0 (0.7) mmol/L, with a mean (sd) difference over follow‐up of‐0.10 (0.5); in the Standard Diet arm baseline and follow‐up [P] were 2.0 (0.6) and 1.9 (0.6) mmol/L, with mean difference over follow‐up of‐0.11 mmol/L (0.5); the mean reduction (sem) in [P] over follow‐up was 0.01 mmol/L (0.11) less in Modified than in Standard arm, p= 0.9. The mean (sd) difference in Follow‐up [K]‐Baseline [K] in the Modified and Standard arms was 0.01 (0.7) and 0.09 (0.6) mmol/L respectively; the mean (sem) increase in [K] over follow‐up was 0.08 mmol/L (0.15) less in Modified than in Standard arm, p= 0.6. Limitations of this study include the modest sample size and limited intervention period (1month); while the intervention was by necessity unblinded, the outcome, serum phosphate, was analysed in a blinded fashion. Conclusions: The liberalized modified renal diet was well tolerated and was associated with almost identical [P] control as compared to the standard diet. The modified renal diet has a wider food choice, is safe and has equally effective [P] control as the standard renal diet.