Objectives: To investigate if a 7-day frequency-volume (FV) chart could identify nocturia on a polyuric basis in patients with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH).
Patients and methods: The study included 23 patients (mean age 62.8 years, range 42-78) with LUTS who were referred for the evaluation of potential BPH and 11 men (control subjects, mean age 63.3 years, range 58-69); all completed a 7-day FV chart investigation as outpatients.
Results: Nocturia was associated with nocturnal polyuria in 10 of 23 patients with LUTS; these 10 patients had a diminished diurnal variation of urine production, whereas 13 patients had a diurnal variation in urine production comparable with that in controls with no nocturia. The degree of nocturia correlated positively with nocturnal urine production but showed no relationship with sleep duration. The nocturnal polyuria in these patients was associated with a higher 24-h urine production and seemed at least partly to be caused by a higher fluid intake during daytime.
Conclusion: Nocturia on a polyuric basis can be detected by using a FV chart. In these patients, a 3-day FV chart would be sufficient to detect nocturia on a polyuric basis and seems therefore to be a valuable tool in evaluating patients with LUTS referred for potential BPH.