Every day, 88% of UK dialysis patients swallow up to 15 phosphate-binding pills to lower their blood phosphate, yet no trial has ever proven this practice saves lives or improves how they feel. This matters because end-stage kidney disease causes phosphate to build up in the blood, and high phosphate is linked to heart attacks and strokes. For decades, doctors have prescribed binders—costing at least £5,000 per patient per year—based on observational data, not randomised evidence. Patients face a crushing pill burden, often skip doses, and report lower quality of life. The PHOSPHATE trial will settle whether this expensive, burdensome treatment actually works. The trial will randomise 3,600 dialysis patients across the UK, Canada, Australia, and New Zealand to either an intensive phosphate target (below 1.5 mmol/L) or a liberal target (2.0–2.5 mmol/L). The primary outcome is cardiovascular death or non-fatal events like heart attack or stroke. Key secondary outcomes include quality of life and cost-effectiveness. If the intensive target shows no benefit, the case for routine binder use collapses—potentially freeing thousands of patients from daily pill regimens and saving the NHS millions. If it does show benefit, the trial provides the first solid evidence to justify current practice. Either way, it ends decades of uncertainty.
View original technical description
RESEARCH QUESTION Does lowering serum phosphate in dialysis patients reduce a cardiovascular (CV) events and CV death? BACKGROUND End Stage Kidney Disease (ESKD) results in phosphate retention and hyperphosphataemia, which is associated with worse outcomes including CV events and mortality. Current treatment guidelines recommend lowering phosphate towards normal through dietary restriction, dialysis and medications called ‘binders’ that prevent its dietary absorption from the gut. Binders have been in use for many decades, and 88% of UK dialysis patients require binders to achieve current targets. Despite preclinical and observational data suggesting an association of hyperphosphataemia with CV mortality, there is no randomised trial evidence that phosphate lowering improves clinical or patient reported outcomes. Binders cost at least £5000 p.a. per patient; their use contributes to one of the highest pill burdens of any chronic disease (up to 15 binders per day), resulting in high non-adherence and reduced quality of life. There is an urgent need for adequately powered trials to assess the effectiveness of the costly and burdensome practice of phosphate lowering. AIMS and OBJECTIVES We will assess the effect of intensive vs. liberal phosphate targets on fatal and non-fatal cardiovascular events and quality of life (HRQoL) in patients receiving dialysis. METHODS We will conduct a pragmatic parallel-group randomised controlled superiority trial of intensive (<1.5 mmol/L) vs liberal (2.0-2.5 mmol/L) phosphate targets to determine effectiveness and cost effectiveness of phosphate lowering in patients receiving dialysis. Setting Dialysis centres in the UK (56%), Canada (27%), New Zealand and Australia (17%) Population Inclusions - Age = 45 years, or age = 18 years with diabetes - Dialysis dependent > 3 months - Prescribed at least one phosphate binder Intervention: Binders to achieve a phosphate target = 1.5 mmol/L. Control: Binders only if serum phosphate > 2.5 mmol/L, with cessation of phosphate binders if phosphate = 2.0 mmol/L. Both groups will receive standard dietary advice at the start of the trial, then as needed to achieve target phosphate. Outcomes: The primary outcome is the time to the composite of CV mortality or non-fatal CV events including acute coronary syndrome, hospitalisation for unstable angina, coronary revascularisation, stroke, peripheral arterial event or peripheral arterial revascularisation. Key secondary outcomes will include: - Health-Related Quality of Life (EQ5D, SF36) - Cost effectiveness Other secondary outcomes are described in the detailed research plan. Sample Size The PHOSPHATE trial will enrol 3600 participants (2000 from the United Kingdom). IMPACT PHOSPHATE will demonstrate whether the current practice of intensive phosphate lowering has clinical benefit or improves quality of life. Clear evidence of benefit is necessary to justify the current scale and consequences of binder prescribing.
Plain English summaries and category classifications on this site are generated by AI and may not perfectly reflect the original research.
Is something wrong? Let us know