Pragmatic randomised trial of High Or Standard PHosphAte Targets in End-stage kidney disease

Principal Investigators:  Sunil Badve and Rathika Krishnasamy
Clinical Project Manager: Peta-Anne Paul-Brent
Clinical Research Associate: Lisan Mulvey
Trial Number: AKTN 17.02

Population: Kidney failure patients on dialysis >45 years or >18 years with diabetes in Australia, New Zealand, Canada and UK.
Intervention: Intensive and liberal target phosphate level
Follow-up: 5 years
Primary outcome: Composite of major cardiovascular events

Status: Open to recruitment
Target Recruitment: 3,600 participants (600 in Australia and New Zealand)

Trial Summary
Although hyperphosphatemia is associated with increased mortality risk in kidney failure patients, the KDIGO Guidelines suggestion of ‘lowering elevated phosphate levels towards the normal range’ is based on low quality evidence. Phosphate- lowering medications, the mainstay of phosphate-lowering treatment, are associated with substantially increased pill burden and non-adherence, adverse gastrointestinal symptoms, poor quality of life; and are extremely expensive. However, RCT evidence demonstrating that treatments that lower serum phosphate will improve patient-centred outcomes, such as survival and how patients feel or function, is still lacking. Currently available evidence demonstrates only an association and not a cause-effect relationship between phosphate and clinical outcomes in patients with kidney failure.

A recent editorial justly asked “How can a medication class achieve 75% prevalence of use in a chronic disease population without evidence of clinical benefit”; and concluded that “Clinical trials of phosphate binders are the only way to determine the potential benefits and harms of these commonly used and expensive medications”. Therefore, an adequately powered RCT is urgently required to evaluate whether reduction of serum phosphate concentration toward the normal level with phosphate-lowering medications reduces the risk of cardiovascular death or non-fatal major cardiovascular events; improves physical health, fatigue, and patient satisfaction in kidney failure patients receiving dialysis; and is cost-effective.