Monitoring the calcium-phosphate product is important

EDITOR,--In Neveen A T Hamdy and colleagues' study of alfacalcidol in chronic renal failure, treatment with phosphate binding agents (other than 500 mg elemental calcium daily) was started only if the serum phosphate concentration was >2.2 mmol/l.1 We believe that the threshold for starting phosphate binding agents should be lower, particularly when alfacalcidol is being given to “maintain serum calcium concentration at the upper limit of the normal laboratory reference range” (2.63 mmol/l).

Metastatic calcification has long been recognised as a complication …