title: Rationalization of interpretation of uroflowmetry for a non-caucasian (Indian) population: conceptual development and validation of volume-normalized flow rate index.
abstract: OBJECTIVE
  We intended to define volume-normalized flow rates (cQ; VQI) and to construct and validate uroflow (Q)-volume (V) nomograms in our Indian (non-Caucasian) population.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Group A, male healthy volunteers 18-45 years without LUTS. Group B, men >18 years with LUTS (IPSS > 7; global QOL > 2). The participants voided in standing on normal-to-strong desire into digital gravimetric uroflowmeter. Data of <50 ml void and intermittent flow was discarded. Reference cQ calculated using (i) Von Garrelts equations (=Q/VV(2)), (ii) cubic equations (=Q/VV(3)). Bladder volume (BV) rather than voided volume (VV) was considered for Q-V relation (BV = VV + PVR). VQI derived from present data were compared with the reference-VQI in terms of differences in area-under-curve of receiver operating characteristics. For comparing sensitivity, specificity and predictive values of study nomograms with Caucasian nomograms (Liverpool and Siroky), data of group-A and -B were plotted on each nomogram and no. of observations above and below the cutoffs (defined as equivalent to -1 SD) manually counted.
  
  
  RESULTS
  Total 542 voids of group-A and 465 of group-B included for final analysis. Q-V relation was best described as [Q ∝ BV(2.4)  ≅ BV(2)]. The derived VQI (=Q/BV(2.4) ≅ Q/BV(2)) fared significantly superior to reference VQI with VV as denominator. Nomograms, constructed on Q ∝ BV(2) , were less sensitive but had higher specificity and positive predictive values compared to Caucasian nomograms.
  
  
  CONCLUSIONS
  Volume-normalized flow-rate index with BV as denominator (Q/BV(2)) is has highly discriminative value in screening for voiding dysfunction. Population-specific Q-BV nomograms are more specific and predictive than Caucasian Q-VV nomograms.
authors: Department of Urology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors: Mayank Mohan
authors: MM
authors: Agarwal
authors: ShivKumar
authors: S
authors: Patil
authors: Kishore
authors: K
authors: Roy
authors: Mayur
authors: M
authors: Bandawar
authors: Sunirmal
authors: S
authors: Choudhury
authors: Ravimohan
authors: R
authors: Mavuduru
authors: Suresh K
authors: SK
authors: Sharma
authors: Arup K
authors: AK
authors: Mandal
authors: Shrawan K
authors: SK
authors: Singh
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D006801:Humans; D007194:India; D059411:Lower Urinary Tract Symptoms / Q000175:diagnosis* / Q000208:ethnology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D049451:Nomograms; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012016:Reference Values; D015203:Reproducibility of Results; D013997:Time Factors; D001743:Urinary Bladder / Q000503:physiopathology*; D001745:Urinary Bladder Diseases / Q000175:diagnosis* / Q000208:ethnology / Q000503:physiopathology; D014563:Urodynamics; D044465:White People; D055815:Young Adult
keywords: average flow rate; corrected flow rate; flow rate index; maximum flow rate; nomogram; uroflowmetry