<p><strong>PURPOSE: </strong>Shockwave lithotripsy (SWL) and ureteroscopy (URS) are the most commonly performed surgeries for kidney and ureteral stones, but the comparative effectiveness of these interventions at the population level is unclear. The purpose of our study was to compare retreatment for SWL and URS.</p>

<p><strong>MATERIALS AND METHODS: </strong>A retrospective cohort study using all-payer claims data for all patients who underwent SWL or URS from 1997-2016 at 74 hospitals in South Carolina was performed. The primary outcome measure was subsequent SWL or URS within 6 months of initial surgery. Pseudorandomized trials of URS versus SWL were performed for each year, applying propensity scores to balance hospital and patient characteristics. Discrete time failure models were fit using propensity-score weighted logistic regression.</p>

<p><strong>RESULTS: </strong>Overall, 136,152 URS and SWL surgeries were performed on 95,227 unique patients with retreatment representing 9% of all surgeries. 74,251 index surgeries were SWL (59.9%) and 49,743 were URS (40.1%). SWL was associated with a 20% increased odds of retreatment (OR 1.20, 95% CI 1.13, 1.26). The probability of retreatment was 7.5% for URS and 10.4% for SWL. SWL had the greatest risk for retreatment at months 2 (OR 1.85, 95% CI 1.64, 2.10) and 3 (OR 1.76, 95% CI: 1.50, 2.06). Initial SWL patients were more likely to have SWL for retreatment (84.6%) than were patients who had initial URS to have URS (29.3%).</p>

<p><strong>CONCLUSIONS: </strong>Compared to URS, SWL was associated with increased odds of retreatment. These results have implications for shared decision-making and value-based surgical treatment of nephrolithiasis.</p>