When is medical prophylaxis cost-effective for recurrent calcium stones?

Purpose: Medical management is generally recommended for recurrent calcium stones to prevent future episodes. However, in this era of extracorporeal shock wave lithotripsy and outpatient ureteroseopy it is not known whether medical prophylaxis is more cost-effective than treatment of recurrent stone episodes. The cost of medical prophylaxis was compared with the cost of clinically managing recurrent stone episodes, and the stone recurrence rate without prophylaxis (stone frequency) at which these 2 treatment approaches became cost equivalent was determined. Materials and Methods: An international cost survey was conducted in 10 countries to compare costs of medical prophylaxis and managing recurrent acute stone episodes. Costs of an acute stone episode included an emergency room visit, associated radiographic imaging to confirm diagnosis of a symptomatic stone and outpatient treatment of upper urinary tract stones that did not pass spontaneously. Costs of medical management included an initial limited metabolic evaluation, drug therapy, a followup office visit every 6 months that included a 24-hour urinalysis and radiographic imaging of the kidneys, ureters and bladder once a year. Results: Costs of medical prophylaxis and managing an acute stone episode varied significantly from country to country. The stone frequency at which costs of these management options became equivalent ranged from 0.3 to 4 stone episodes a year. Conclusions: Medical management of a first stone episode is not cost-effective. Cost analysis should be individualized for specific health care plans to determine which practice patterns are most cost-effective for a particular patient with recurrent calcium stone formation.