Practice variation in the surgical management of urinary lithiasis

Purpose: Shock wave lithotripsy and ureteroscopy are highly effective treatments for urinary lithiasis. While stone size and location are primary determinants of therapy, little is known about other factors associated with treatment. We identified patient, provider and practice setting characteristics associated with the selection of ureteroscopy or shock wave lithotripsy. Materials and Methods: We used the Medicare 5% sample to identify beneficiaries with an incident stone encounter from 1997 to 2007. Within this group we identified beneficiaries undergoing shock wave lithotripsy or ureteroscopy for the management of urinary calculi. Multivariable regression models identified factors associated with the use of ureteroscopy. Results: The cohort comprised 9,358 beneficiaries who underwent an initial procedure. Shock wave lithotripsy was used in 5,208 (56%) beneficiaries while ureteroscopy was used in 4,150 (44%). Female patients were less likely than males to undergo ureteroscopy (OR 0.844, p = 0.006). Providers who more recently completed residency training used ureteroscopy more often (p = 0.023). Provider and facility volume were associated with initial procedure selection. The odds of a second procedure following initial shock wave lithotripsy were 1.54 times those of ureteroscopy (p <0.001). Conclusions: Nonclinical factors are associated with the use of ureteroscopy or shock wave lithotripsy for initial stone management, which may reflect provider and/or patient preferences or experience. Further investigation is required to understand the impact of these outcomes on quality and cost of care.