Development And Validation Of A Nomogram For Bladder Outlet Obstruction In Elderly Male Patients With Benign Prostatic Hyperplasia Complicated Bladder Stones

PurposeTo explore the relationship between bladder outlet obstruction(BOO)and benign prostatic hyperplasia(BPH)complicated bladder stones,and to select other risk factors of bladder stones;to develop and validate a nomogram for predicting BOO in elderly male patients with BPH complicated bladder stones.MethodsInformation of 367 patients with BPH treated in our hospital from January 2018 to December 2018 was retrospectively collected,including age,weight,height(based on which BMI was calculated),prostate volume(PV),residual urine volume(PVR),bladder stones,maximum urinary flow rate(Qmax),results of urodynamic tests,prostate specific antigen(PSA),serum uric acid,urine pH,urine specific gravity,urine nitrite,urine occult blood,urine white blood cells,and urine culture.Univariate and multivariate logistic regression was conducted to select independent risk factors for BPH complicated bladder stones.Information of 303 patients with BPH complicated bladder stones treated in our hospital from October 2014 to December 2018 was retrospectively collected,including age,BMI,PV,PVR,bladder stone morphology,maximum length of stones,and Qmax.Independent predictors of BOO in elderly patients with BPH complicated bladder stones were selected by logistic regression analysis.A nomogram was developed and internally validated accordinglyResultsUnivariate analysis of the risk factors of bladder stones showed that BOO(OR 0.829,95%confidence interval[CI]:0.402?1.709,P=0.611)was not significantly associated with bladder stones,while urine leukocytes(OR=1.188,95%CI:0.999?1.413,P=0.051)and urinary occult blood(OR=1.165,95%confidence interval 0.985?1.378,P=0.075)was.Multivariate logistic regression furtherly showed that urinary leukocytes(OR=1.240,95%CI:1.025?1.500,P=0.027)was an independent risk factor for bladder stones.In the second part of the study,a nomogram for predicting BOO was developed.Four indicators were included in the final model,including age,BMI,PVR,and bladder stone morphology.The bias-corrected C index was 0.658(0.587?0.729)indicating a good discrimination.The Hosmer and Lemeshow test was insignificant indicating a good calibrationConclusionBOO is not an independent risk factor for BPH complicated bladder stones while Urine leukocytes is.This study innovatively developed a non-invasive simple nomogram for patients with BPH complicated bladder stones to predict their risk of BOO.In practice,this nomogram is a good tool for diagnoing BOO and provides reference for decision-making of patients with BPH complicated bladder stones when invasive urodynamic tests are not appropriate.