Balancing dietary restrictions with effective phosphate binder use was a key theme of the CKD-MBD presentations at the ASN Kidney Week 2016 congress in Chicago.
Results from the FrEDI study
During an educational symposium on balancing the various strategies to manage hyperphosphatemia, Professor Kalantar-Zadeh presented results from the FrEDI study.  In avoiding foods with high phosphorus content, dialysis patients often end up with a low-protein diet, a significant predictor of mortality in haemodialysis patients. The FrEDI study looked at the effect of providing hypoalbuminaemic dialysis patients with either:
- a high-protein meal during dialysis combined with a potent phosphate binder (the meal contained 50-55g protein and 400-500mg phosphorus), or
- a low-protein, low-phosphorus meal during dialysis (<1 g protein and <20mg phosphorus)
The primary composite outcome was a rise in serum albumin of ≥0.2 g/dL while maintaining phosphorus between 3.5–<5.5mg/dL. Of the patients receiving the high-protein meals, 27% achieved an increase in serum albumin and controlled serum phosphorus compared with 12% in the low-protein meal group.
A meaningful rise in interleukin-6 level was reported in 31% of the patients in the low-protein group versus 9% in the high-protein group. Prof Kalantar-Zadeh and colleagues concluded that combining high-protein meals with a potent phosphate binder during dialysis in hypoalbuminaemic patients is safe and effective in increasing serum albumin while controlling serum phosphorus.
During discussion it was noted that the provision of such meals during dialysis was relatively commonplace in some European countries, but was not part of standard clinical practice in the United States.
Why did the recent update to the US Nutrition Facts label not mandate the inclusion of phosphorus content?
In a popular presentation on Thursday afternoon, Mona Calvo reviewed the recent changes to the US Nutrition Facts label and outlines why phosphorus content was not mandated for inclusion. She explained to the audience that:
- The FDA’s view was that Nutrition Facts label information “has never been, nor is it now, targeted to individuals with acute or chronic disease (including CKD)”; as a result, phosphorus content was not listed as a mandatory requirement in nutrition labels, except where the item was fortified with phosphorus
- The daily values for phosphorus were increased from 1000 mg/d to 1250 mg/d in the May 2016 label update; both physicians and patients needed to be aware of this when reviewing % calculations of daily values
- There was no differentiation required in terms of labelling organic and inorganic phosphate
Real-world data on sucroferric oxyhydroixide
Several posters presented at ASN Kidney Week reported real-world data relating to the use of sucroferric oxyhydroxide (SO).
Dr Linda Ficociello et al. used the DOPPS database to highlight the high levels of hyperphosphatemia in haemodialysis patients (36%), despite widespread use of phosphate binders. They then looked at the phosphorus levels and pill burden over a 12-month period in 306 haemodialysis patients who had been prescribed SO:
- At baseline, the mean serum phosphorus was 7.0mg/dl, with only 17.5% of patients achieving a serum phosphorus target of ≤5.5mg/dl.
- In the 12 months of SO prescription, 31% -42% of patients achieved a serum phosphorus ≤5.5mg/dl, an increase of >75% compared to baseline.
- The significant change in serum phosphorus was accompanied by a reduction in pill burden, from 8.3 pills/day at baseline to 4.1-4.3 in the 12 months of SO.
In a second poster, Dr Ficociello et al. looked specifically at the changes when patients switched from calcium acetate to SO. This analysis also showed a significant increase in patients achieving target serum phosphorus (from 15.8% at baseline to a high of 36.7% with SO) whilst experiencing a reduced pill burden (from 8.5 with calcium acetate to 4-4.5 with SO).
The same team also looked at patients switching from sevelamer to SO. Again, a greater percentage of patients achieved serum phosphorus target of ≤5.5mg/dl with a significantly reduced pill burden.
Pill burden can be a significant barrier to compliance in patients with chronic kidney disease, and these real-world studies suggest that greater control of serum phosphorus can be achieved at a lower pill burden with SO.[2-4]
- Kamyar Kalantar-Zadeh. http://ndt.oxfordjournals.org/content/early/2016/10/20/ndt.gfw323
- Abstract: [FR-PO420] Serum Phosphorus and Pill Number per Day in Hyperphosphatemic Hemodialysis Patients (n=306) Prescribed Sucroferric Oxyhydroxide for 12 Months. http://www.abstracts2view.com/asn_2016/view.php?nu=2103&terms=&type=abstract
- Abstract: [FR-PO421] Pill Burden and Serum Phosphorus in Hemodialysis Patients Switched from Calcium Acetate to Sucroferric Oxyhydroxide as Part of Routine Care. http://www.abstracts2view.com/asn_2016/view.php?nu=4844&terms=&type=abstract
- Abstract: [FR-PO428] Pill Burden and Serum Phosphorus in Hemodialysis Patients Switched from Sevelamer to Sucroferric Oxyhydroxide. http://www.abstracts2view.com/asn_2016/view.php?nu=4787&terms=&type=abstract