Pharmacological interventions for preventing complications in idiopathic hypercalciuria

Idiopathic hypercalciuria is an inherited metabolic abnormality characterised by excessive amounts of calcium excreted into the urine in patients with normal serum levels of calcium. The main complications of this disease in adults are the formation of kidney stones and bone loss. In children, hypercalciuria can cause recurrent haematuria (blood in the urine), frequency-dysuria syndrome (frequent painful or difficult urination), urinary tract infection and abdominal and back pain. The aim of this review was to evaluate the benefits and harms of drug treatments for preventing the complications of idiopathic hypercalciuria. We identified four studies comparing thiazides (diuretics) with either standard treatment of clinical follow-up and increased water intake or specific dietary recommendations and one study comparing thiazides plus a potassium salt. There was a decrease in the number of new stones in the group receiving thiazides as well as an increase in the time taken for new stone formation. The addition of potassium salts to thiazide treatment significantly reduced the amount of calcium excreted in the urine. No studies in children were identified and there were no studies investigating the use of drug treatment for those with hypercalciuria but were symptom free.