Introduction

To assess the cost-effectiveness of observation vs. intervention on asymptomatic residual fragments less than 4mm in diameter following ureteroscopic laser lithotripsy using a decision analysis model.

Methods

:Outcomes data from a previously published analysis of residual fragments after ureteroscopic lithotripsy were utilized. A decision analysis model was constructed to compare the cost-effectiveness of initial observation of residual fragments compared to immediate intervention. Cost for the observation arm consisted of ED visits, hospitalizations, and re-interventions. The cost-analysis model extended for 3 years to account for delayed re-intervention rates on fragments of this size. Expected value calculations and sensitivity analyses were performed to determine the optimal treatment pathway based on overall cost-effectiveness.

Results

Two hundred thirty-two patients were found to have asymptomatic residual fragments < 4mm on follow-up imaging following ureteroscopic lithotripsy. There were 191 patients in the observation group and 41 in the immediate-intervention group. Decision analysis modeling demonstrated that when comparing initial observation to immediate re-intervention, the cost was $2965 vs. $4504, respectively. The difference in cost was largely driven by the fact that over 3 years, approximately 56% of patients remain asymptomatic without ED visit, readmission or re-intervention wherease 44% of patients incurred at least one of those 3 complications. This represents an approximate annual per-patient savings of $513, and $1539 over three years when observation is selected over immediate re-intervention.

Conclusions

Our decision analysis model demonstrates superior cost-effectiveness for observation over immediate re-intervention for asymptomatic residual stones < 4mm following ureteroscopic lithotripsy. The cost-savings are primarily due to a plurality of patients not requiring intervention if observed. Based on these findings, careful stratification and selection of patients may enable surgeons to improve cost-effectiveness of managing small, asymptomatic residual fragments following ureteroscopic lithotripsy.

Funding

none