STONE DISEASE

Cost-effectiveness of medical expulsive therapy using alpha-blockers for the treatment of distal ureteral stones
Bensalah K, Pearle M, Lotan Y
Department of Urology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States
Eur Urol. 2008; 53: 411-9

• Objective: Medical expulsive therapy (MET) has recently emerged as an efficacious and safe option for the initial management of ureteral stones. The objective of this study was to assess the cost-effectiveness of MET compared with conservative therapy for the treatment of ureteral stones using international cost data from the United States and four European countries.
• Material and Methods: A decision analysis model was built with the use of TreeAge Pro 2004 software with linear success rate assumptions. The likelihood of spontaneous passage of ureteral stones according to their size and location was estimated with the use of data derived from a published meta-analysis. The estimated cost of ureteroscopy (URS) in the United States ($4973) was based on the mean cost of 121 consecutive cases performed at a large metropolitan hospital. URS costs for other countries were obtained from a published international survey. The cost of tamsulosin ($2.08 per day), currently the most commonly used medical expulsive agent, was estimated as a mean of the costs obtained from two national pharmacy chains. MET and conservative therapies were compared with the use of one-way and two-way sensitivity analyses.
• Results: In the United States, MET using tamsulosin resulted in a $1132 cost advantage over observation. MET maintained its cost advantage even in countries where the cost of URS is much lower than in the United States. Two-way sensitivity analysis showed that MET remained cost-effective even with very low rates of spontaneous passage, minimal benefit of MET, or low cost of URS.
• Conclusion: MET is a cost-effective strategy for the management of distal ureteral stones-even those with a low rate of spontaneous passage-providing another incentive for initial “facilitated observation” before embarking on surgical intervention.
  
  
• Editorial Comment
  Medical expulsive therapy has gained acceptance as a safe and efficacious option for the management of ureteral calculi, and is now incorporated into the new American Urological Association practice guidelines for ureteral stones. The authors present an elaborate evaluation of the cost-effectiveness of medical expulsive therapy (MET) compared to conservative therapy for ureteral stones from a global perspective.
  One might argue that the acute management of renal colic and the postoperative course following ureteroscopy is not uniformly conducted in the outpatient setting, as assumed in the decision model. Though based on a historical metaanalysis, the spontaneous stone passage rates utilized in this decision making tree (< 4 mm 38%, > 6 mm 1%) is lower than more recent studies would suggest for distal ureteral stones. Indeed, in our practice we would counsel patients with a 3 mm distal stone that they have a 70% chance of spontaneous stone passage and a patient with a 6 mm distal stone would have a 30% chance (1). This aspect of the study design would accentuate the cost-advantages of MET predicted by the decision making model. The authors assumed that the cost of follow-up would be the same in each group; however, one would anticipate that the need for follow-up imaging, unanticipated emergency room visits and lost wages would be lower in the MET group. This aspect of the study design would diminish the potential cost-benefit for the MET approach.
  As such, the study serves the important function of quantifying the expected - that improving stone passage will save money in addition to saving patient morbidity. It highlights the large discrepancy in global health care costs – a topic for another day.
  Reference

1. Coll DM, Varanelli MJ, Smith RC: Relationship of spontaneous passage of ureteral calculi to stone size and location as revealed by unenhanced helical CT. AJR Am J Roentgenol. 2002; 178: 101-3.

Dr. Manoj Monga
Professor, Department of Urology
University of Minnesota
Edina, Minnesota, USA