A one-day frequency-volume chart is representative of a 3-day chart in the assessment of lower urinary tract symptoms suggestive of bladder outflow obstruction

Introduction: 24-h frequency-volume (FV) charts are often used to assess patients with lower urinary tract symptoms suggestive of bladder outflow obstruction (LUTS/BOO). There are no clear guidelines regarding the optimum chart duration. We aimed to determine whether a one-day FV chart is representative of a 3-day equivalent. Patients and methods: Men presenting with LUTS (including nocturia) were prospectively recruited and completed a 3-day FV chart. Exclusion criteria were previous bladder outflow surgery and anti-cholinergic medication. Results: 285 patients were recruited (mean age, 67 years; range 26-93 years). There were no significant inter-day differences in 24-h urine volume (24HUV) (p=0.10) and functional bladder capacity (FBC) (p=0.19). However, there were significant differences identified between days 1 and 2, and 1 and 3 for both nocturnal urine volume (NUV) (p<0.001) and actual nocturnal voids (ANV) (p<0.001) despite significant correlation of these parameters on each day with their respective 3-day means. Conclusion: Our data suggest that a one-day FV chart is representative of a 3-day equivalent for the assessment of 24HUV and FBC in patients with LUTS/BOO. Further studies are required to compare the repeatability and clinical utility of a one-day chart compared with 3- and 7-day charts, particularly in patients with nocturia.