title: International Prostatic Symptom Score-voiding/storage subscore ratio in association with total prostatic volume and maximum flow rate is diagnostic of bladder outlet-related lower urinary tract dysfunction in men with lower urinary tract symptoms.
abstract: OBJECTIVE
  The aim of this study was to investigate the predictive values of the total International Prostate Symptom Score (IPSS-T) and voiding to storage subscore ratio (IPSS-V/S) in association with total prostate volume (TPV) and maximum urinary flow rate (Qmax) in the diagnosis of bladder outlet-related lower urinary tract dysfunction (LUTD) in men with lower urinary tract symptoms (LUTS).
  
  
  METHODS
  A total of 298 men with LUTS were enrolled. Video-urodynamic studies were used to determine the causes of LUTS. Differences in IPSS-T, IPSS-V/S ratio, TPV and Qmax between patients with bladder outlet-related LUTD and bladder-related LUTD were analyzed. The positive and negative predictive values (PPV and NPV) for bladder outlet-related LUTD were calculated using these parameters.
  
  
  RESULTS
  Of the 298 men, bladder outlet-related LUTD was diagnosed in 167 (56%). We found that IPSS-V/S ratio was significantly higher among those patients with bladder outlet-related LUTD than patients with bladder-related LUTD (2.28±2.25 vs. 0.90±0.88, p<0.001). TPV was similar between the two groups; however, in contrast to patients with bladder-related LUTD, patients with bladder outlet-related LUTD had higher detrusor voiding pressure, lower Qmax values, and greater postvoid residual volumes. The combination of TPV≥30 ml and Qmax≤10 ml/sec had a PPV of 68.8% and a NPV of 53.5% for bladder outlet-related LUTD. When IPSS-T≥12 or IPSS-T≥15 was considered as an additional criterion, PPV increased to 75.0% and 78.5%, respectively, and the NPV decreased to 50.9% and 50.2%, respectively. When IPSS-V/S>1 or >2 was factored into the equation instead of IPSS-T, PPV were 91.4% and 97.3%, respectively, and NPV were 54.8% and 49.8%, respectively.
  
  
  CONCLUSIONS
  Combination of IPSS-T with TPV and Qmax increases the PPV of bladder outlet-related LUTD. Furthermore, including IPSS-V/S>1 or >2 into the equation results in a higher PPV than IPSS-T. IPSS-V/S>1 is a stronger predictor of bladder outlet-related LUTD than IPSS-T.
authors.affiliation: Department of Urology, Buddhist Tzu Chi General Hospital and Tzu Chi University, Hualien, Taiwan.
authors.forename: Yuan-Hong
authors.initials: YH
authors.lastname: Jiang
authors.forename: Victor Chia-Hsiang
authors.initials: VC
authors.lastname: Lin
authors.forename: Chun-Hou
authors.initials: CH
authors.lastname: Liao
authors.forename: Hann-Chorng
authors.initials: HC
authors.lastname: Kuo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D059411:Lower Urinary Tract Symptoms / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009929:Organ Size / Q000502:physiology; D011237:Predictive Value of Tests; D011467:Prostate / Q000473:pathology*; D012107:Research Design; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013624:Taiwan; D001748:Urinary Bladder Neck Obstruction / Q000175:diagnosis* / Q000503:physiopathology; D014554:Urination / Q000502:physiology*