Introduction: The bladder storage function has a homeostatic system that continuously varies voided volume at each void in response to changes in bladder filling rate. Specifically, high diuresis increases the voided volume at each voiding, and low diuresis decreases the voided volume at each voiding. Attention has recently focused on this system named vesical adaptation response to diuresis (VARD). We have reported that patients with lower urinary tract symptoms (LUTS) lacked VARD (Haga et al. PLoS One, 2016). Although VARD seems to be important to maintain lower urinary tract function, the clinical feature and significance of VARD remains unknown. Therefore, the aim of this study is to determine what factors influence VARD in male patients with LUTS. Methods: Ninety-four male patients older than 60 years old (age 76.5 ± 6.6 years) with LUTS who attended our hospital between 2017 and 2019 were included in this study. Overactive Bladder Symptom Score (OABSS), 24-h frequency-volume charts (FVCs), uroflowmetry, and ultrasonography to measure prostate volume were evaluated. Exclusion criteria were apparent neurogenic lower urinary tract dysfunction, acute urinary tract infection, and needed urethral catheterization. VARD was defined by the presence of a significant correlation coefficient (?) between urine output rate and voided volume at each voiding on FVCs (?>0.4, P<0.05). According to the presence or absence of VARD, patients were divided into two groups: VARD presence (n=48) and VARD absence groups (n=46). The patient characteristics and parameters of lower urinary tract functions were compared between two groups, with P < 0.05 considered significant. Results: The number of OAB patients was significantly higher in the VARD absence group than in the VARD presence group (P=0.04). The prostate volume tended to be higher in VARD absence group. The multivariate analysis revealed that OAB and prostate enlargement (BPE) were significantly related to the VARD absence group (OAB: aOR 3.76, 95%CI: 1.34-10.6, P=0.01, BPE: aOR = 1.04, 95% CI: 1.01-1.07, P=0.02). Conclusions: The OAB and BPE were independent risk factors for the lack of VARD in male LUTS patients. Increased afferent nerve activity from the lower urinary tract associated with OAB and BPE might lack VARD, resulting in increased urinary frequency during a high-diuretic phase. The VARD could be more a useful objective marker to measure the bladder storage function than the symptom questionnaire for LUTS. SOURCE OF Funding: Nothing
