Abstract
PurposeTo develop and validate a new clinical prediction model that accurately predicts the failure of shockwave lithotripsy (SWL) using information obtained from non-contrast-enhanced computed tomography (NCCT).MethodsThis multicentre retrospective cohort study consecutively enrolled patients diagnosed with upper urinary tract calculi by NCCT at five hospitals in Japan from January 1, 2006 to December 31, 2016. Among the candidate predictors, we selected the six most significant predictors a priori. The main outcome was SWL failure after three sessions. Model calibration was evaluated by the calibration slope and the Hosmer–Lemeshow test. Discrimination was evaluated by the receiver-operating characteristic curves and the area under the curve (AUC). A multivariable logistic regression analysis was performed; based on the estimated β coefficients, predictive scores were generated.ResultsOf 2695 patients, 2271 were included. Patients were divided into the development cohort (1666 patients) and validation cohort (605 patients) according to geographical factors. We developed a clinical prediction model with scores ranging from 0 to 49 points. We named the prediction model the S3HoCKwave score based on the initials of the predictors (sex, skin-to-stone distance, size, Hounsfield units, colic, and kidney or ureter). As a result of internal validation, the optimism-corrected AUC was 0.72. In the validation cohort, the Hosmer–Lemeshow test did not show statistical significance (P = 0.33), and the AUC was 0.71 (95% confidence interval 0.65–0.76).ConclusionsThe S3HoCKwave score is easy to understand, has a relatively high predictive value, and allows clinicians to make appropriate treatment selections.
Highlights
Upper urinary tract calculi are common, with a prevalence of 5.2% during 1988–1994 [1], and increasing trends in the United StatesMembers of the Okayama-Ehime shockwave lithotripsy (SWL) Study Group are listed in the Acknowledgements section.Electronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.Extended author information available on the last page of the article and Japan [2]
We developed and validated a new clinical prediction model called the S 3HoCKwave score
The S3HoCKwave score is based on the sum score and consists of only six predictors; it is very easy for clinicians to use and understand compared to the clinical nomogram [22]
Summary
Upper urinary tract calculi (i.e., kidney stones and ureteral stones) are common, with a prevalence of 5.2% during 1988–1994 [1], and increasing trends in the United States. Members of the Okayama-Ehime SWL Study Group are listed in the Acknowledgements section. Extended author information available on the last page of the article and Japan [2]. Symptoms of upper urinary tract calculi vary and are sometimes serious [3]. Upper urinary tract calculi can be complicated by sepsis, which can be fatal [4]. Early diagnosis and early treatment interventions for upper urinary tract calculi are important in clinical practice
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