Objectives: To assess epidemiological and chronological trends of upper urinary tract stones in Japan in 2015.Methods: Patients with a first episode of upper urinary tract stones in 2015 were enrolled in this nationwide survey. The study included all hospitals approved by the Japanese Board of Urology, therefore covering most of the hospitals where urologists practice in Japan. The annual incidence and composition of urolithiasis were evaluated by age and sex. These results were compared with the previous results of the nationwide surveys from 1965 to 2005 to analyze temporal trends. Results: The estimated annual incidence of a first-episode upper urinary tract stone in 2015 was 137.9 (191.9 in men and 86.9 in women) per 100 000. The estimated agestandardized first-episode upper urinary tract stone incidence in 2015 was 107.8 (150.6 in men and 63.3 in women) per 100 000, which did not represent a significant increase since 2005. An equivalent incidence was observed in patients aged >50 years, whereas a reduced incidence was observed in patients aged <50 years in both sexes. The proportion of patients who received percutaneous nephrolithotomy and/or ureteroscopy increased by approximately fivefold in the past 10 years. Conclusions: The steady increase in the annual incidence of upper urinary tract stones since 1955 leveled off in 2015. The current results show novel trends in the incidence and treatment modalities in the nationwide surveys of urolithiasis in Japan.
Objectives
To determine changes and trends in the annual incidence and epidemiological aspects of lower urinary tract stones in Japan.
Methods
Data about patients who had been diagnosed by urologists in 2015 with first and recurrent lower urinary tract stones were collected from 301 hospitals approved by the Japanese Board of Urology. The estimated annual incidence according to sex, age and stone composition was compared with previous nationwide surveys between 1965 and 2005.
Results
The incidence of lower urinary tract stones in Japan has steadily increased from 4.7 per 100 000 in 1965 to 12.0 per 100 000 in 2015. However, the age standardized annual incidence of lower urinary tract stones has remained relatively stable over the same period at 5.5 per 100 000 and 6.0 per 100 000 in 1965 and 2015, respectively. The increase in incidence was most evident among individuals aged ≥80 years. The incidence of calcium oxalate stones has steadily increased among males and females, whereas that of infection‐related stones has significantly decreased from 26.2% to 14.3% among men over the past 50 years.
Conclusions
Nationwide surveys suggest a steady increase in the incidence of lower urinary tract stones over a 50‐year period in Japan. This trend might reflect changes in the aging population and improved Japanese medical standards.
Purpose To 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). Methods This 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. Results Of 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 S 3 HoCKwave 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 optimismcorrected 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). Conclusions The S 3 HoCKwave score is easy to understand, has a relatively high predictive value, and allows clinicians to make appropriate treatment selections. Keywords Urolithiasis • Extracorporeal shockwave therapy • Decision making • Decision support techniques Members of the Okayama-Ehime SWL Study Group are listed in the Acknowledgements section.
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