Performance of ‘Triple-D’ and ‘Quadruple-D’ scores compared to a regression-based predictive model for treatment outcomes in extracorporeal shock wave lithotripsy
DOI:
https://doi.org/10.4081/aiua.2025.14265Keywords:
Extracorporeal shock wave lithotripsy, predictive model, triple-D score, quadruple-D score, stone clearance, kidney stones, ureteric stones, logistic regression, outcome prediction, predictive scoring systemsAbstract
Background: Extracorporeal shock wave lithotripsy (ESWL) is a widely utilized, noninvasive treatment for renal and ureteric stones. Accurate prediction of treatment outcomes is essential for improving patient counseling and optimizing clinical management. Established scoring systems, such as the ‘Triple-D’ score – which incorporates stone Density, Diameter, and skin-to-stone Distance –and the ‘Quadruple-D’ score – which adds factors like stone location or hydronephrosis status – are used to stratify patients by risk. However, these tools have limitations in predictive accuracy. This study aimed to evaluate and compare the predictive performances of the Triple-D and Quadruple-D scores against a novel regression-based model for ESWL outcomes.
Methods: A retrospective study was conducted on 1,000 adult patients treated with ESWL using the Dornier Compact Delta® III Pro lithotripter from May 2022 to November 2023. Key predictors of ESWL failure were identified using multivariable logistic regression with internal validation. Predictive performances were compared using receiver operating characteristic (ROC) analysis, with statistical differences assessed by DeLong’s test. Model calibration and clinical utility were examined through calibration plots and decision curve analysis (DCA).
Results: ESWL treatment success was achieved in 87.5% of patients. Independent predictors of failure included prior urologic intervention (adjusted odds ratio [aOR] 2.64, 95% CI 1.75-3.99), multiple stones (aOR 0.45, 95% CI 0.24-0.77), higher stone density (per 100 Hounsfield Units increase; p<0.001), and increased skin-to-stone distance (per cm; aOR 1.18, 95% CI 1.06-1.30). The regression-based model showed superior discrimination (AUC 0.92) compared to the Quadruple-D (AUC 0.81, p=0.01) and Triple-D (AUC 0.72, p<0.001) scores. Calibration and DCA confirmed the model’s improved accuracy and clinical benefit.
Conclusions: The regression-based model outperforms existing Triple-D and Quadruple-D scores in predicting ESWL failure, providing enhanced individualized risk stratification. This may facilitate better patient selection and treatment planning. Prospective validation is warranted.
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