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ORIGINAL ARTICLE   Free accessfree

Minerva Urologica e Nefrologica 2019 October;71(5):531-6

DOI: 10.23736/S0393-2249.18.03243-5


language: English

External validation of Imamura nomogram as a tool to predict preoperatively laser semi-rigid ureterolithotripsy outcomes

Cosimo DE NUNZIO 1 , Mariangela BELLANGINO 1, Olivia A. VOGLINO 1, Valeria BALDASSARRI 1, Riccardo LOMBARDO 1, Matteo PIGNATELLI 2, Giorgia TEMA 1, Eva BERARDI 2, Antonio CREMONA 2, Andrea TUBARO 1

1 Department of Urology, Sant’Andrea Hospital, Sapienza University, Rome, Italy; 2 Department of Radiology, Sant’Andrea Hospital, Sapienza University, Rome, Italy

BACKGROUND: We aimed to validate Imamura nomogram for prediction of stone free rate in patients undergoing ureterolithotripsy (ULT).
METHODS: From January 2013 to June 2016, patients undergoing laser semi-rigid ULT were prospectively enrolled at our center. All patients were preoperatively assessed with clinical history, blood samples, uranalysis and non-contrast enhanced computed tomography (CT). Treatment efficacy was assessed 1 month later by non-contrast enhanced CT. ROC curve was used to evaluate the performance characteristics of Imamura nomogram.
RESULTS: Overall, we enrolled 275 patients. Median age was 55 years (IQR: 46/64), median length of stone was 9.8 mm (IQR: 7.5/12). Pyuria was detected in 6/275 (2.1%) patients. Stones were located at ureteropelvic junction in 55/275 (19%) patients, proximal ureter in 74/275 (26%) patients, middle and distal ureter in 66/275 (24%) patients and 82/275 (30%) patients, respectively. At 1-month follow-up, 209/275 (76%) patients were stone free. Imamura nomogram presented an AUC of 0.67 (95% CI: 0.580-0.761) for the prediction of stone free rate. At the best cut-off value of 75%, sensitivity was 76%, specificity was 55%, positive predictive value (PPV) was 83% and negative predictive value was 45%.
CONCLUSIONS: We firstly validated Imamura nomogram in a European cohort study. It proved a reasonable accuracy (area under curve: 0.67) and a good PPV (83%). Further studies should confirm our results to support the routine clinical use of Imamura nomogram as a tool to predict ULT outcomes.

KEY WORDS: Nomograms; Ureteral calculi; Lithotripsy; Patient outcome assessment

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