Management of ureteral calculi: A cost comparison and decision making analysis

Purpose: We compared the cost of treatment strategies for ureteral calculi using a decision tree model. Materials and Methods: A comprehensive literature review was performed to determine the average success rate of each of 3 treatment modalities, namely observation, ureteroscopy and shock wave lithotripsy. Using these success rates decision analysis models were constructed using Data 3.5 software (TreeAge Software, Inc., Williamstown, Massachusetts) to estimate the cost of treatment and followup for each of the 3 treatments. One-way sensitivity analysis was performed to evaluate the effect of varying individual probabilities of success and costs, and 2-way sensitivity analysis was done to evaluate the model for a wide range of potential costs and success rates of ureteroscopy and shock wave lithotripsy. In addition, a table was constructed to enable individual surgeons and institutions to determine the cost impact of ureteroscopy and shock wave lithotripsy in their unique clinical scenarios. Results: Observation was the least costly pathway if no financial cost, such as emergency room visits, was incurred by failed observation. Ureteroscopy was less costly than shock wave lithotripsy for stones at all ureteral locations. A cost difference between the 2 modalities of approximately $1,440, $1,670 and $1,750 was noted for proximal, mid and distal ureteral calculi, respectively. One-way sensitivity analysis showed that the cost of ureteroscopy would have to increase by more than $1,400, $1,700 and $1,850, and the success rate would have to decrease by 28%, 36% and 39% for proximal, mid and distal stones, respectively, before reaching cost equivalence with shock wave lithotripsy. Likewise, the cost of shock wave lithotripsy would have to decrease by more than $1,489 to achieve cost equivalence with ureteroscopy. Overall ureteroscopy was more cost-effective at all stone sites regardless of the success rate of shock wave lithotripsy. Conclusions: Ureteroscopy is the most cost-effective treatment strategy for ureteral stones at all locations after observation fails. The high cost of purchasing and maintaining a lithotriptor is responsible for the high treatment cost associated with shock wave lithotripsy. However, cost is only one of a number of important factors that are considered when determining an appropriate treatment strategy.