Treatment of renal osteodystrophy

Seek specialist advice. Some summary points regarding management of renal osteodystrophy are presented below:

• antiresorptive treatment (e.g. with bisphosphonates) for suspected or proven reduced bone mineral density should not be commenced in patients with chronic kidney disease (CKD) until treatable disorders of calcium, phosphate, PTH and serum 25-hydroxyvitamin D metabolism have been sought and treated
• no measurements of calcium, phosphate, or PTH are required in stage 1 or 2 CKD unless the patient has suspected or proven reduced bone mineral density
• in stage 3 CKD, serum corrected calcium and phosphate should be measured every 12 months
  • abnormal values should be confirmed on a repeat fasting sample taken without a tourniquet. Patients with confirmed abnormalities of serum corrected calcium or phosphate should be referred to a nephrologist
• in stage 3 CKD, plasma or serum PTH should be checked when the diagnosis of CKD stage 3 is first made
  • if the PTH is < 70 ng/L, no further checking is required unless the patient progresses to stage 4 CKD
  • if the PTH is > 70 ng/L, serum 25-hydroxyvitamin D should be checked. If the serum 25- hydroxyvitamin D is low (<80 nmol/L, 30 µg/L), therapy should be commenced with ergocalciferol or colecalciferol in a preparation that contains calcium carbonate or calcium lactate but not calcium phosphate; or colecalciferol monthly by intramuscular injection. PTH should then be rechecked after 3 months of replacement therapy. There is no need to repeat the measurement of serum 25- hydroxyvitamin D unless non-adherence or malabsorption is suspected. Vitamin D therapy should be continued long-term unless the clinical situation changes
• if the PTH is > 70 ng/L despite a normal serum 25-hydroxyvitamin D or treatment with ergocalciferol or colecalciferol, the patient should be referred to a nephrologist for specialist advice on management of hyperparathyroidism

Notes:

• when using vitamin D therapy calcium levels should initially be monitored weekly for possible hypercalcaemia. As the serum calcium becomes more stable, monitoring can be monthly
• parathyroidectomy may be indicated in severe disease. However, it is to be avoided if aluminium deposits are observed in bone because of the increased risk of subsequent aluminium toxicity
• to convert PTH (ng/L) to SI units (pmol/L) multiply by 0.11

Reference:

1. The Renal Association (May 2006).UK CKD Guidelines