Hypothesis / aims of study
Nocturia is one of the most prevalent symptoms of LUTS. The causes of nocturia include bladder storage disorder, sleep disorder, and nocturnal polyuria. Nocturnal polyuria is considered the largest contributor among these factors. Relation between nocturia and non-dipping blood pressure has been already indicated. However, there is no study that indicated the relation between nocturnal polyuria and blood pressure variability. We hypothesized that nocturnal polyuria and blood pressure variability are related. In this study, we investigate the factors of nocturnal polyuria, and the relation between nocturnal polyuria and blood pressure variability in male patients with LUTS.
Study design, materials and methods
242 male patients with LUTS who were treated recorded frequency volume charts. We investigated their urinary condition and characteristics, medical history, and medications based on their medical charts. 34 patients among these patients underwent ambulatory blood pressure monitoring (ABPM) for 24 hours to evaluate blood pressure variability.
Functional bladder capacity (FBC) is maximum voided volume. Reduced FBC is maximum voided volume of <4 ml/kg × body weight. Nocturnal polyuria is defined as Nocturnal polyuria index (Npi) >0.33.
We assessed the date according to the guidelines for the clinical use of 24-h ABPM (JCS 2010). Extreme dipper, dipper, and non-dipper were defined as nocturnal systolic blood pressure declined ≥20%,10-19%, and 0-9%, respectively. Riser was defined as nocturnal systolic blood pressure risen. We classified extreme dippers and dippers into “dipping”, and non-dipper and riser into “non-dipping”.
Interpretation of results
Among patients with nocturia who were treated, the frequency of reduced FBC was low(13.4%) and, the frequency of nocturnal polyuria was relativity high(67.0%).It was indicated that bladder storage disorders were adequately treated and, the approach for nocturnal polyuria might be needed for treatment for nocturia.
Patients who used two or more anti-hypertensives were present at a significant higher rate in the NP group than in NNP group. It was considered that nocturnal polyuria would have relation to resistant hypertension. Patients with non-dipping blood pressure were present at a significant higher rate in the NP group than NNP group. Our results suggest that nocturnal polyuria is related to non-dipping blood pressure.