Analysis of Nocturia Determinants Using a Novel Portable Urine-Measuring Device.

Aims: To investigate the relationship between nocturia and values measured using a novel multifunctional portable urine-measuring device.

Methods: Thirty-five older men with nocturia and/or high-normal or high blood pressure were enrolled to record measurements on one full day (24 h) and two nights using the portable device during urination. Participants used a semi-conical cup with a small hole equipped with a conductivity sensor, temperature sensor, and timer to measure urine volume, salt content, urine temperature, and urination speed.

Results: Two participants were excluded owing to oliguria. The mean age of 33 participants was 75.2 ± 7.4 years (range: 55-85 years). The mean nocturnal urination frequency, including the first urination after waking, was 2.1 ± 0.6 times. Simple correlation analysis revealed that nocturnal urine frequency significantly increased with nocturnal urine volume (r = 0.65, p < 0.001) and salt content (r = 0.57, p < 0.001) but not with 24-h urine volume and salt content. Furthermore, the frequency significantly decreased with nocturnal urine temperature (r = -0.37, p < 0.05). No significant relationship was observed between morning blood pressure and nocturnal urination frequency. A high correlation was observed between nighttime urine volume and salt content (r = 0.73, p < 0.001).

Conclusions: Nocturnal urine volume, salt content, and urine temperature are significantly correlated with nocturia. The portable urine-measuring device could guide nocturia reduction through facilitation of the reduction of nocturnal urine volume and salt content, in addition to urine temperature monitoring.