Lack of Change in the Adaptation Ability of the Bladder for the Urine Production Rate in Aged Men with Nocturia

Abstract

Introduction: To investigate the association between bladder capacity and the urine production rate in aged men with or without nocturia using a frequency volume chart (FVC). Materials and Methods: One-hundred and thirty-eight men aged 65–80 years were enrolled. After the International Prostate Symptom Score (IPSS) and 3 consecutive days FVC were evaluated, men were divided into 2 groups: Nocturia group, with any total IPSS, and ≥1.5 micturition on average at night; and Control group, with total IPSS < 8 and < 1.5 micturition on average at night. Each parameter was compared between the 2 groups using unpaired t tests. Linear and multiple regression analyses were performed between the urine production rate and volume/voids. Results: Men numbering 45 and 21 were assigned to the Nocturia and Control groups respectively. There were no differences in background factors between the 2 groups. Volume/voids positively correlated with the urine production rate in both groups for day and night. A multivariate regression model also showed the same results. In the Control group, the degree of slope at night was higher than that during the day. However, in the Nocturia group, there were no differences in the degree of slope between day and night. Conclusions: This novel finding has led to a possibility for resolving nocturia.