Analysis of nocturia with 24-h urine volume, nocturnal urine volume, nocturnal bladder capacity and length of sleep duration: concept for effective treatment modality.

OBJECTIVE: • To determine the relationship between the number of nocturia and 24-h urine volume, nocturnal urine volume, nocturnal bladder capacity and length of sleep duration as well as to assess the significance of these factors with respect to eliminating nocturnal voidings in individual patients with nocturia. PATIENTS AND METHODS: • Among 532 participants who completed a 3-day bladder diary between April 2005 and December 2006, the diaries of 450 participants without 24-h polyuria were analyzed. • Clinical variables such as the number of daytime and night-time voids, 24-h urine volume, nocturnal polyuria index, daytime and night-time maximum voided volumes (MVV), night/day MVV ratio, sleep duration and proportion of night/day urine production rates were obtained from each diary. • Participants were classified into eight groups according to values of three factors: nocturnal MVV, proportion of night/day urine production rates and length of sleep duration. • Each group was divided into three subgroups: non-nocturics (number of nocturnal voidings is zero), mild nocturics (number of nocturnal voidings is one) and severe nocturics (number of nocturnal voidings is two or more). • The data from non-nocturics with three normal factors were regarded as the normal control and compared with the variables of the other subgroups using Dunnett's method. RESULTS: • Variables that form the basis of classifying participants into eight groups and corresponding to abnormal factors of each group were statistically significant in all the subgroups of each group. • Furthermore, a significantly increased 24-h urine volume was found in severe nocturics of the group with three normal factors. • A significantly decreased 24-h urine volume was found in non-nocturics of groups with nocturnal polyuria, decreased bladder capacity and both long sleep duration and nocturnal polyuria. • A significantly increased nocturnal MVV and night/day MVV ratio were shown in non-nocturics and mild nocturics of the groups with nocturnal polyuria and both long sleep duration and nocturnal polyuria. CONCLUSIONS: • Because nocturia is a multifactorial disorder and closely related to four factors (i.e. 24-h urine volume, nocturnal urine volume, nocturnal bladder capacity and length of sleep duration), the evaluation of all these factors appears to be clinically useful for determining the main contributing factor in patients with nocturia as well as the suitable treatment modality on an individual basis. • Physicians should take all these factors into consideration in the evaluation and treatment of nocturia.

Sleep duration is an independent factor in nocturia: analysis of bladder diaries.

OBJECTIVE To analyse the relationship between the number of nocturia episodes and other variables obtained from a bladder diary, with special attention to the duration of sleep, as nocturia is closely related to sleep disorders. PATIENTS, SUBJECTS AND METHODS Between April 2005 and December 2006, 532 participants, including both community-dwelling subjects who underwent a mass screening programme and outpatients who consulted the department of urology, completed a 3-day bladder diary. Clinical variables, i.e. the number of daytime and night-time voids, diurnal and nocturnal urine volume, daytime and night-time maximum voided volume, sleep duration and nocturnal polyuria index (NPi) were obtained from the diary. The variables were assessed by univariate analysis in all participants, and by multiple regression analysis of all participants, males, females, subjects in mass screening and those with no 24-h polyuria, to determine which variables were independently associated with the number of nocturia episodes. RESULTS Univariate analysis showed a considerable correlation between the nocturia episodes and age, nocturnal urine volume, NPi and sleep duration. On multiple regression analysis, age, nocturnal urine volume, night-time maximum voided volume and sleep duration were independently related to number of nocturia episodes in all subgroups. CONCLUSIONS Sleep duration was confirmed as an independent factor in nocturia. Sleep conditions, including sleep duration, should be considered when evaluating and treating patients with nocturia.