[Predictive score of success adapted to our environment to improve results of extracorporeal lithotripsy].

Objective: To present a predictive tool of success of ESWL adapted to our environment.

Methods: We performed a retrospective, descriptive and analytical study of patients with renal and upper ureteral stones whom underwent ESWL with DUET MAGNA lithotripter between January 2014 and March 2015. We included 114 patients in whom demographics and CT scan characteristics were studied. Multivariate analysis by logistic regression was performed to establish independent predictors of success in ESWL. A ROC curve was used to determine success cut-off values of ESWL in each significant variable. The score was established based on the numbers of variables under the cut-off value in each patient. In every one of these categories, percentage of stone free was determined. Finally, the area under the curve of our ESWL treatment success score was made.

Results: Of 114 patients studied, 58 (51%) were stone free. After multivariate study, independent predictors of success with ESWL were tomographic density of lithiasis (UH), body mass index (BMI) and stone diameter (mm). Ideal cut off points of treatment success in each one of the score parameters were: density of lithiasis 900 UH, BMI 27 and lithiasis diameter 11 mm. Percentage of stone free was 31.8% for score 0, 37.1% for score 1, 57.5% for score 2 and 88.3% for score 3. Area under the curve for the score was 0.723 (p<0.001).

Conclusions: This score could represent a predictive tool in our environment to predict ESWL results. Utilization of this score could limit the use of this therapy only to patients with favorable profile (score2-3) improving in this way cost-effectiveness of this procedure.