title: Urodynamic Features and Significant Predictors of Bladder Outlet Obstruction in Patients With Lower Urinary Tract Symptoms/Benign Prostatic Hyperplasia and Small Prostate Volume.
abstract: OBJECTIVE
  To investigate the clinical and urodynamic features of patients with lower urinary tract symptoms/benign prostatic hyperplasia (LUTS/BPH) according to their prostate size.
  
  
  METHODS
  We analyzed 2039 LUTS/BPH patients who underwent urodynamic study between October 2004 and August 2013. We divided the patients into three groups according to their prostate size: small (≤30 mL), moderately enlarged (31-80 mL), and large prostate (≥81 mL) groups. We compared the groups regarding age, International Prostatic Symptom Score, maximal flow rate (Qmax), postvoided residual (PVR), serum prostate-specific antigen, prostate volume measured by ultrasonography, and urodynamic findings.
  
  
  RESULTS
  Patients with a small prostate had better urodynamic outcomes than those with larger prostates in overall population. Although the total prostate volume significantly correlated with the bladder outlet obstruction (BOO) index (r  =  0.51), BOO patients with a small prostate had similar Qmax, higher PVR, and lower voiding efficiency, compared to those with larger prostates. Moreover, urodynamic parameters indicating bladder abnormalities, including low compliance and involuntary detrusor contraction positivity, were similar among the groups in BOO patients. A higher proportion of detrusor underactivity was also observed in the small prostate group in BOO patients. Finally, when adjusting for potential confounding variables, we identified serum prostate-specific antigen levels (odds ratio, 1.34) and Qmax (odds ratio, 0.77) as significant predictors for BOO in LUTS/BPH patients with a small prostate.
  
  
  CONCLUSIONS
  BOO patients with a small prostate showed higher PVR and poor voiding efficiency, as well as similar urodynamic bladder abnormalities, compared to those with moderately enlarged and large prostates.
authors.affiliation: Department of Urology, Seoul National University Bundang Hospital, Seong-nam si, Gyeonggi-do, Republic of Korea.
authors.forename: Minyong
authors.initials: M
authors.lastname: Kang
authors.affiliation: Department of Urology, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Myong
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Urology, Dongtan Sacred Heart Hospital, Hwaseong, Gyeonggi-do, Republic of Korea.
authors.forename: Min Soo
authors.initials: MS
authors.lastname: Choo
authors.affiliation: Department of Urology, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Jae-Seung
authors.initials: JS
authors.lastname: Paick
authors.affiliation: Department of Urology, Seoul National University Hospital, Seoul, Republic of Korea. Electronic address: sjo@snu.ac.kr.
authors.forename: Seung-June
authors.initials: SJ
authors.lastname: Oh
mesh_terms: D000368:Aged; D006801:Humans; D059411:Lower Urinary Tract Symptoms / Q000150:complications / Q000503:physiopathology*; D008297:Male; D009929:Organ Size; D011379:Prognosis; D011467:Prostate / Q000473:pathology*; D011470:Prostatic Hyperplasia / Q000150:complications / Q000503:physiopathology*; D012189:Retrospective Studies; D001748:Urinary Bladder Neck Obstruction / Q000150:complications / Q000503:physiopathology*; D014563:Urodynamics