PHOS GRAPH a novel tool in hyperphosphataemia management in haemodialysis patients
Authors: Chandrasekharan L. , Ramlan G. , Harnett P. , Almond M.K. , Worrall S. 
Published: July 2008

Background:  In patients with end stage renal disease, hyperphosphataemia is an almost universal complication. Prolonged hyperphosphataemia is associated with increased morbidity and mortality (Kidney Disease Outcomes Quality Initiative‐K/DOQI, 2004). Pharmacological interventions such as phosphate binders are important in the management of hyperphosphataemia, but these need to be complemented by education regarding binder compliance with phosphate containing foods and limiting excessive phosphate intake. A previous audit carried out in September 2006 of the ‘knowledge of haemodialysis patients on a low phosphate diet and binders’ clearly indicated that we need to improve patients’ knowledge to achieve better control of hyperphosphataemia. The purpose of the study was to assess the effectiveness of an innovative method of patient education (Phos Graph) on the management of serum phosphate in haemodialysis patients with persistent hyperphosphataemia.

Methods:  The renal dietitians and the renal multi disciplinary team devised a tool called the Phos Graph. The Phos Graph is a novel patient information tool, to inform patients of their phosphate levels relative to their peers on dialysis. The Graph shows the upper limit and lower limit of the normal range, the patient's value for the month as well as their value for the previous month and a rank in comparison to their dialysis peers. Thirty‐four (of 129 patients on haemodialysis) patients with phosphate levels >1.8 mM were identified at the beginning of the study. These patients received a copy of the Phos Graph, an individual dietary assessment and a review of their low phosphate diet by the renal specialist dietitians. This study was carried out for three consecutive months (April to June 2007). The mean serum phosphate levels at the start and finish of the study were compared using the paired student two tailed t‐test. Statistical significance was taken at the P‐value <0.05.

Results:  Table 1 shows the comparison of phosphate levels for patients who received both, the Phos Graph and dietary intervention and those who received only Phos Graph.

 Mean phosphate levels during the 3 month study period

Phosphate (mM)
Start of study
End of study
P value

>1.8 (Phos Graph + dietary intervention) n = 34
2.42
2.16
<0.05

<1.8 (Phos Graph without dietary intervention) n = 95
1.29
1.43
<0.05

Discussion:  The study showed that there was a statistically significant reduction in phosphate levels during July 2007 for the 34 patients identified with raised levels in April 2007. However, the mean phosphate level at the end of the study is still above the recommended national level.

Conclusion:  In this pilot study ‘Phos Graph’ has proved to be a good tool to assist patients in managing hyperphosphataemia. However, it is difficult to distinguish whether it was the Phos Graph or individualized dietary care or both that resulted in improvements in serum phosphate levels. Further work on a larger group is needed to clarify this issue.

Acknowledgment:  We would like to thank Matthew Jones (Renal systems manager) and also to all Renal staff for their valuable support.

References  Block et al. (2004) Mineral metabolism, morbidity and mortality in maintenance haemodialysis patients. J. Am. Soc. Nephrol.15, 2208–2218.

Kidney Disease Outcomes Quality Initiative (KDOQI). (2002) Clinical Practice Guidelines for Bone Metabolism and Disease in Chronic Kidney Disease, Guideline 3. Evaluation of Serum Phosphorus Levels.

Renal Association. Renal Association Standards Committee. (2002) Treatment of adults and children with renal failure: standards and audit measures, 3rd edn. Royal College of Physicians, London.

The UK Renal Registry. (2005) Chapter 10: Bone Biochemistry: Serum Phosphate, Calcium, Parathyroid Hormone, Albumin and Aluminium. 8th Annual Report.