Objectives

To clarify how vesical adaptation response, the homeostatic system that constantly changes voided volume to adapt to diuresis, is involved in male lower urinary tract symptoms and bladder storage function.

Methods

We included male patients older than 65 years with lower urinary tract symptoms. Vesical adaptation response to diuresis was defined as a positive correlation between urine output rate and voided volume on 3-day sensory-related frequency volume charts. Patients were divided into two groups according to the presence or absence of vesical adaptation response to diuresis, and characteristics were compared between groups.

Results

Ninety-four male patients were finally analyzed. Vesical adaptation response to diuresis was found in 48 patients (51%) and was lacking in 46 patients (49%). Patients without vesical adaptation response to diuresis were significantly more often diagnosed with overactive bladder (P = 0.04). After adjusting for confounders, absence of vesical adaptation response to diuresis was significantly associated with overactive bladder (adjusted odds ratio 3.76, 95% confidence interval 1.34–10.55; P = 0.01) and benign prostatic enlargement (adjusted odds ratio 1.04, 95% confidence interval 1.01–1.07; P = 0.02).

Conclusions

The absence of vesical adaptation response to diuresis, characterized by decreased voided volume during a diuretic phase, can be interpreted as a form of bladder storage dysfunction. Assessment of vesical adaptation response to diuresis may provide a new index of bladder storage function and contribute to a better understanding of the pathophysiology underlying bladder storage dysfunction in patients with lower urinary tract symptoms.