Background and purpose: Nocturia is a common complaint in sleep-disordered breathing (SDB), but there is no study demonstrating the prevalence and frequency of nocturnal urination in a large number of SDB patients. To determine the prevalence and frequency of nocturnal urination among patients with SDB of different severities and to discover the factors related to nocturia.
Method: A retrospective chart review was conducted among 1970 SDB patients. Nocturia was assessed using a standard questionnaire. Four groups of SDB patients were compared with regard to frequency of nocturnal urination and additional demographic, clinical, and polysomnographic (PSG) variables, by analysis of variance (ANOVA) with Tukey's honest significant difference (HSD) post-hoc comparisons. Partial correlation analysis was performed to detect the relationships between frequency of nocturnal urination and PSG and demographic variables. Logistic regression analysis was employed to examine the independent predictors of nocturia.
Results: Significant correlations were found between the frequency of nocturnal urination and mean age, body mass index (BMI), respiratory disturbance index (RDI), apnea-hypopnea index (AHI), respiratory effort index (REI) and lowest oxygen saturation. The frequency of nocturnal urination showed significant differences between four groups of individuals with SDB (P<0.001). Nocturnal urination of more than three episodes per night was reported significantly more by severe SDB patients (P<0.001).
Conclusion: Age, BMI, hypertension (HT), AHI, and REI were found to be significantly associated with nocturia.