Fig. 4

A Receiver operating characteristic curves of hydronephrosis, RIL, RIW, stone burden, and number of calyces involved. The variables stone burden and number of calyces involved both showed highly accurate predictive abilities of (AUC = 0.727, CI = 0.668–0.785), and (AUC = 0.751, CI = 0.703–0.798), respectively. On the other hand, the variables RIL, RIW, and hydronephrosis showed less accurate predictive abilities of (AUC = 0.601, CI = 0.548–0.655), (AUC = 0.558, CI = 0.504–0.611), and (AUC = 0.590, CI = 0.531–0.650) respectively. B Receiver operating characteristic curves of the Joint index. The joint indicators showed a highly accurate predictive ability (AUC = 0.811, CI = 0.766–0.856)