An evidence-based approach to hypercalciuria: is it really necessary for the study of the role of calcium in urolithiasis?
An abnormally raised 24-h urinary excretion of calcium has long been regarded as a common feature of calcium stone disease. However, hypercalciuria can be defined only by reference to a range of values measured in a representative population of individuals who have never suffered from stone disease. To date, there have been significant flaws in all published studies reporting normal ranges for daily urinary calcium excretion. There is no doubt that additional, carefully performed and documented investigations need to be undertaken to establish what is truly abnormal for a given population; the persistent use of arbitrarily defined limits may be hindering rather than helping to unravel the role of calcium in the pathogenesis of calcium stones.
Marshall
V R
VR
Department of Surgery, Flinders Medical Centre, Bedford Park, South Australia.
Ryall
R L
RL