title: The optimal duration of frequency-volume charts related to compliance and reliability.
abstract: OBJECTIVE
  To assess Frequency-volume charts (FVCs) for the yield of additional recorded days and the ideal duration of recording related to compliance and reliability.
  
  
  METHODS
  Of 500 consecutive urologic outpatients willing to complete a 7-day FVC, 378 FVCs were evaluable. During seven consecutive days every voiding time and volume were recorded. Missed entries were indicated with a coded letter, thereby assessing the true frequency and compliance. Reliability is the agreement of the day-to-day FVC parameters with the 7-day FVC pattern. Single-day reliability was assessed and used in the Spearman-Brown formula.
  
  
  RESULTS
  FVCs of 228 male and 150 females were evaluated. Mean age was 55.2 years (standard deviation [SD]: 16.2 years), and mean 24-hr urine production was 1,856 ml (SD: 828 ml). The percentage of patients with complete FVCs decreased from 78% on day 2 to 58% on day 7, and dropped below 70% after 4 days. Single-day reliability was r = 0.63 for nocturnal urine production, r = 0.72 for 24-hr urine production, and r = 0.80 for mean voided volume. At 5 days, reliability of 90% was achieved for all parameters.
  
  
  CONCLUSIONS
  With each additional day, FVCs showed a decrease in compliance and an increase in reliability. At day 3, reliability of 80% was achieved for all FVC parameters, but compliance dropped to 73%. Beyond 5 days, the yield of additional recorded days was limited. We advocate an FVC duration of 3 days, but the duration may be shortened or extended depending on the goal of the FVC.
authors.affiliation: Department of Urology, Sint Lucas Andreas Ziekenhuis, Amsterdam, The Netherlands.
authors.forename: Ernst P
authors.initials: EP
authors.lastname: van Haarst
authors.forename: J L H Ruud
authors.initials: JL
authors.lastname: Bosch
mesh_terms: D000328:Adult; D000368:Aged; D003950:Diagnostic Techniques, Urological; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D059411:Lower Urinary Tract Symptoms / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D013997:Time Factors; D001743:Urinary Bladder / Q000503:physiopathology*; D001745:Urinary Bladder Diseases / Q000175:diagnosis* / Q000503:physiopathology; D014554:Urination; D014563:Urodynamics
keywords: compliance; frequency-volume chart; reliability; self report; urinary bladder; urination