PREFERENCE-BASED ASSESSMENT Patient Utility Measurement for Managing Ureteral Stones: A Modified Standard Gamble Approach

Objectives: To measure the utility of patients with ureteral stones under various medical regimes and to identify significant factors affecting utility for various health states. Methods: A cross-sectional survey was conducted to measure the utility of 89 patients on each health state related to the clinical management of ureteral stones. Health states with respect to intervention and treatment modalities were classified into the acute phase (including medication, extracorporeal shock wave lithotripsy, ureterorenoscopic lithotripsy, and surgery) and the chronic phase (no specific intervention, lifestyle modification, maintenance with surveillance, and continued medication). Utility was measured by using the modified standard gamble. Demographic data and relevant history of treatment modalities and interventions for ureteral stones were collected by using a questionnaire. Results: Utility scores of health states in the acute phase (ranging from 0.914 [surgery] to 0.967 [extracorporeal shock wave lithotripsy]) were lower than those in the chronic phase (ranging from 0.955 [maintenance with surveillance] to 0.974 [lifestyle modification]). Utility for surgery was lower than for nonsurgical methods. Utilities for the two lithotripsy modalities were close to that for medication. The utility figures for health states in the chronic phase were the highest for lifestyle modification, but the differences across health states were trivial. Sex, history of ureterorenoscopic lithotripsy, education level, and employment were significant covariates in the final multiple linear regression model. Conclusions: A modified standard gamble chained method was applied to measure the utility for health states in relation to the clinical management of ureteral stones. Patients preferred nonsurgical treatment over surgical treatment and hemodialysis regardless of health states. We also found that sex, a history of ureterorenoscopic lithotripsy, education level, and employment affected utility for health states related to clinical management. Our findings provide an insight into patient preference for the choice of treatment of ureteral stones.