Sleep analysis of patients with nocturia and benign prostatic obstruction

To analyze the timing of nocturia during sleep and its effect on sleep quality using the polysomnography (PSG) findings from patients with benign prostatic obstruction.

From August 2009 to August 2010, 20 patients diagnosed with benign prostatic obstruction were enrolled in the present study. The sleep evaluation was performed by PSG. The Epworth index was used to evaluate the sleepiness of the patients. The effect of nocturia on sleep quality is evaluated by sleep efficacy, total sleep time, and rapid eye movement sleep duration, calculated from the hypnograms derived from the polysomnograms.

The mean age, total International Prostate Symptom Score, nocturia frequency on International Prostate Symptom Score, and frequency of nocturia recorded during PSG was 60.4 ± 8.5 years (range 44-74), 19.3 ± 4.9 (range 10-28), 3.5 ± 1.05 (range 2-5), and 1.35 ± 1.2 (range 0-4), respectively. In 6 patients (30%), the Epworth sleepiness score was pathologic (score >8). Nocturia correlated positively with increased daytime sleepiness, however it did not correlate with sleep efficacy or total sleep time. These parameters were affected by the apnea-hypopnea index, the major determinant of obstructive sleep apnea. Of the 20 patients, 14 (70%) experienced nocturia during PSG, and in these patients, we recorded 23 nocturia episodes that mostly occurred in the superficial sleep stage (16 [70%] of 23). Only 7 nocturia episodes (30%) occurred in the deep sleep stage. The sleep quality of patients with deep sleep nocturia did not differ from that of patients with superficial sleep nocturia.

The results of our study have shown that nocturia predominantly occurs during the superficial sleep or rapid eye movement stage and is related to increased daytime sleepiness in patients with benign prostatic obstruction. The timing and frequency of nocturia had no significant affect on sleep quality; however, the presence of obstructive sleep apnea negatively interfered with these parameters.