Development of Decision Support Formulas for the Prediction of Bladder Outlet Obstruction and Prostatic Surgery in Patients With Lower Urinary Tract Symptom/Benign Prostatic Hyperplasia: Part I, Development of the Formula and its Internal Validation

INJ INTERNATIONAL NEUROUROLOGY JOURNAL pISSN 2093-4777 eISSN 2093-6931 Original Article Volume 19 | Number 2 | June 2015 pages 131-210 INTERNATIONAL NEUROUROLOGY JOURNAL Int Neurourol J 2017;21 Suppl 1:S55-65 https://doi.org/10.5213/inj.1734852.426 pISSN 2093-4777 · eISSN 2093-6931 Official Journal of Korean Continence Society / Korean Society of Urological Research / The Korean Children’s Continence and Enuresis Society / The Korean Association of Urogenital Tract Infection and Inflammation einj.org Mobile Web Development of Decision Support Formulas for the Prediction of Bladder Outlet Obstruction and Prostatic Surgery in Patients With Lower Urinary Tract Symptom/Benign Prostatic Hyperplasia: Part I, Development of the Formula and its Internal Validation Min Soo Choo1, Changwon Yoo2, Sung Yong Cho3, Seong Jin Jeong4, Chang Wook Jeong5, Ja Hyeon Ku5, Seung-June Oh5 Department of Urology, Hallym University Dongtan Sacred Heart Hospital, Hwaseong, Korea Department of Biostatistics, Robert-Stempel College of Public Health & Social Work, Florida International University, Miami, FL, USA 3 Department of Urology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea 4 Department of Urology, Seoul National University Bundang Hospital, Seongnam, Korea 5 Department of Urology, Seoul National University Hospital, Seoul, Korea 1 2 CROSSMARK_logo_3_Test 1/1 https://crossmark-cdn.crossref.org/widget/v2.0/logos/CROSSMARK_Color_square.svg 2017-03-16 Purpose: As the elderly population increases, a growing number of patients have lower urinary tract symptom (LUTS)/benign prostatic hyperplasia (BPH). The aim of this study was to develop decision support formulas and nomograms for the prediction of bladder outlet obstruction (BOO) and for BOO-related surgical decision-making, and to validate them in patients with LUTS/BPH. Methods: Patient with LUTS/BPH between October 2004 and May 2014 were enrolled as a development cohort. The available variables included age, International Prostate Symptom Score, free uroflowmetry, postvoid residual volume, total prostate volume, and the results of a pressure-flow study. A causal Bayesian network analysis was used to identify relevant parameters. Using multivariate logistic regression analysis, formulas were developed to calculate the probabilities of having BOO and requiring prostatic surgery. Patients between June 2014 and December 2015 were prospectively enrolled for internal validation. Receiver operating characteristic curve analysis, calibration plots, and decision curve analysis were performed. Results: A total of 1,179 male patients with LUTS/BPH, with a mean age of 66.1 years, were included as a development cohort. Another 253 patients were enrolled as an internal validation cohort. Using multivariate logistic regression analysis, 2 and 4 formulas were established to estimate the probabilities of having BOO and requiring prostatic surgery, respectively. Our analysis of the predictive accuracy of the model revealed area under the curve values of 0.82 for BOO and 0.87 for prostatic surgery. The sensitivity and specificity were 53.6% and 87.0% for BOO, and 91.6% and 50.0% for prostatic surgery, respectively. The calibration plot indicated that these prediction models showed a good correspondence. In addition, the decision curve analysis showed a high net benefit across the entire spectrum of probability thresholds. Conclusions: We established nomograms for the prediction of BOO and BOO-related prostatic surgery in patients with LUTS/BPH. Internal validation of the nomograms demonstrated that they predicted both having BOO and requiring prostatic surgery very well. Keywords: Prostatic Hyperplasia; Decision Support Systems, Clinical; Nomograms; Urinary Bladder Neck Obstruction; Prostatectomy • Fund/Grant Support: This study was supported by grant from the Seoul National University Hospital Research Fund (34-2014-0100). • Research Ethics: This study was approved by the Institutional Review Board of Seoul National University Hospital (approval number: H-1406119-591). • Conflict of Interest: MSC, a member of the Editorial Board of INJ, is the first author of this article. However, he played no role whatsoever in the editorial evaluation of this article or the decision to publish it. No potential conflict of interest relevant to this article was reported. Corresponding author: Seung-June Oh http://orcid.org/0000-0002-0322-3539 Department of Urology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea E-mail: / Tel +82-2-2072-2406 / Fax: +82-2-742-4665 Submitted: March 22, 2017 / Accepted after revision: April 7, 2017 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright © 2017 Korean Continence Society www.einj.org INJ Choo, et al. • Nomogram of Predicting BOO and Prostatic Surgery INTRODUCTION MATERIALS AND METHODS As the elderly population increases, a growing number of patients have lower urinary tract symptom (LUTS)/benign prostatic hyperplasia (BPH) [1]. The treatment of BPH includes watchful waiting, medical management, and surgical treatment. Medication has been widely used in patients with mild to borderline symptoms. The guidelines of the European Urological Association and the American Urological Association indicate that surgical treatment is necessary when patients have urinary retention, renal insufficiency, recurrent urinary tract infections, bladder stone, or gross hematuria due to an enlarged prostate [2,3]. However, most patients with LUTS/BPH we encounter in clinical practice do not fall under the above absolute indications. Surgery is additionally needed when patients do not experience adequate relief from LUTS with conservative or medical treatment [2]. This relative surgical indication usually reflects the subjective judgment of the surgeon, and/or patients’ degree of compliance and preference for surgery [3]. In real clinical situations, the decision is not simple. It is sometimes difficult to make a clear decision about the treatment of those who do not have an absolute indication for prostatic surgery. Therefore, the development of objective therapeutic guidance is necessary. LUTS/BPH is a progressive disease that can eventually cause irreversible changes in bladder function, especially if bladder outlet obstruction (BOO) is already present. Therefore, when BOO is evident in patients with bothersome LUTS, surgical treatment should be considered. A pressure-flow study (PFS) is currently considered the gold standard for diagnosing BOO; however, it is an invasive and time-consuming procedure. Noninvasive or less invasive modalities have not been fully validated for clinical use. (...truncated)