Is obstructive sleep apnea syndrome related to nocturia?

Objective: The aim of this study was to investigate the relationship between obstructive sleep apnea syndrome (OSAS) and lower urinary tract symptoms (LUTS) in patients with benign prostatic hyperplasia (BPH).

Methods: This multicenter study was performed on 122 male patients with dyspnea and/or sleep disorder. Patient characteristics were recorded. All patients underwent full-night polysomnography, and the apnea-hypopnea index (AHI) was calculated. LUTS were evaluated using the International Prostate Symptom Score (IPSS) and prostate volume was calculated by transabdominal ultrasonography. Based on the AHI, patients were classified as normal or as having mild, moderate, or severe OSAS. Regression analyses were performed to identify independent predictive factors associated with nocturia.

Results: Severe, moderate, and mild OSAS was present in 53, nine, and 46 patients, respectively, where 14 patients with dyspnea and sleep disorder were classified as normal. There were no significant differences between the severe and mild OSAS groups with regard to age, body mass index, systolic and diastolic blood pressure, smoking history, fluid intake, and serum creatinine and glucose concentrations. However, there was a significant difference between two groups in AHI (P < 0.001), nocturia (P < 0.001), and nocturnal voided volume (P = 0.011). Univariate and multivariate analyses revealed that age, smoking history, and an AHI >15 were independent predictors of nocturia.

Conclusions: Sleep disorders are thought to be one reason for nocturia and nocturnal polyuria. Thus, OSAS must be considered in BPH patients who predominantly have storage symptoms.