Hyperphosphataemia in chronic kidney disease (CKD)

• hyperphosphataemia in chronic kidney disease
  
  
  • as kidney dysfunction advances, there is a higher risk of mortality and some comorbidities become more severe
    • hyperphosphataemia is one example of this, and occurs because of insufficient filtering of phosphate from the blood by poorly functioning kidneys. This means that a certain amount of the phosphate does not leave the body in the urine, instead remaining in the blood at abnormally elevated levels
    • high serum phosphate levels can directly and indirectly increase parathyroid hormone secretion, leading to the development of secondary hyperparathyroidism. Left untreated, secondary hyperparathyroidism increases morbidity and mortality and may lead to renal bone disease, with people experiencing bone and muscular pain, increased incidence of fracture, abnormalities of bone and joint morphology, and vascular and soft tissue calcification
      
      
  • target serum phosphate
    • for adults with stage 4 or 5 CKD who are not on dialysis, the UK Renal Association guidelines recommend that serum phosphate be maintained at between 0.9 and 1.5 mmol/l. For adults with stage 5 CKD who are on dialysis, it is recommended that serum phosphate levels be maintained at between 1.1 and 1.7 mmol/l
    • because of the improved removal of phosphate from the blood through dialysis, adults on dialysis have different recommended levels to those with stage 4 or 5 CKD who are not on dialysis
      
      
  • standard management of hyperphosphataemia involves the use of both pharmacological and non-pharmacological interventions, as well as the provision of education and support
    
    
    • dietary management: children, young people and adults
      • a specialist renal dietitian, supported by healthcare professionals with the necessary skills and competencies, should carry out a dietary assessment and give individualised information and advice on dietary phosphate management
        
        
    • phosphate binders: children and young people
      • for children and young people
        • offer a calcium-based phosphate binder as the first-line phosphate binder to control serum phosphate in addition to dietary management
        • if a series of serum calcium measurements shows a trend towards the age-adjusted upper limit of normal, consider a calcium-based binder in combination with sevelamer hydrochloride, having taken into account other causes of rising calcium levels
        • for children and young people who remain hyperphosphataemic despite adherence to a calcium-based phosphate binder, and whose serum calcium goes above the age-adjusted upper limit of normal, consider:
          • either combining with, or switching to, sevelamer hydrochloride,having taken into account other causes of raised calcium
            
            
    • phosphate binders: adults
      • for adults
        • offer calcium acetate as the first-line phosphate binder to control serum phosphate in addition to dietary management
        • consider calcium carbonate if calcium acetate is not tolerated or patients find it unpalatable
          
          
      • for adults with stage 4 or 5 chronic kidney disease (CKD) who are not on dialysis and who are taking a calcium-based binder:
        • consider switching to a non-calcium-based binder if calcium-based phosphate binders are not tolerated
        • consider either combining with, or switching to, a non-calcium-based binder if hypercalcaemia develops (having taken into account other causes of raised calcium), or if serum parathyroid hormone levels are low
          
          
      • review of treatments: children, young people and adults
        • at every routine clinical review, assess the patient's serum phosphate control, taking into account:
          • dietary phosphate management
          • phosphate binder regimen
          • adherence to diet and
          • medication other factors that influence phosphate control, such as vitamin D or dialysis.

Reference:

• (1) NICE (March 2013). Hyperphosphataemia in chronic kidney disease