A prospective observational study on the predictability of Triple-D score versus Quadruple-D score in the success rate of extracorporeal shock wave lithotripsy of renal stones 1–2 cm in diameter

INTRODUCTION: The aim of the study is to evaluate the clinical efficacy of Triple-D scoring system versus Quadruple-D scoring system for assessing stone-free rate (SFR) in individuals with renal stones measuring 1–2 cm in diameter after extracorporeal shock wave lithotripsy (ESWL). MATERIALS AND METHODS: The study was conducted on 120 patients who presented to a tertiary care center in eastern India. Systemic random sampling technique was applied with a sampling interval of 2. Triple-D scoring system comprising of three computed tomography based metrics – stone dimension (volume), stone density (Hounsfield unit), and skin-to-stone distance (SSD) was done before ESWL. Stone location was included as an additional parameter to formulate Quadruple-D scoring system where an extra score was given for stones in the non-lower polar region. Stone-free status was assessed by plain abdominal radiography 3 weeks after ESWL. RESULTS: In the study population, stone dimension, stone density, and stone location were positive predictors of SFR after ESWL whereas age, sex, and body mass index of the patients, laterality of the stone and SSD were not. The area under the curve of Triple-D and Quadruple-D scoring systems were 0.598 and 0.674. CONCLUSION: Triple-D scoring system has been successfully validated as the SFR showed a parallel increase with every positive component. The Quadruple-D scoring system with a simple addition of stone location can further facilitate the validation of Triple-D scoring by increasing SFR, keeping the calculation simple and easy to use. These findings support the incorporation of Quadruple-D scoring system over Triple-D scoring system.