Clinical predictors of nocturia in the sleep apnea population

OBJECTIVES: This study aims to evaluate clinical predictors of nocturia in patients with obstructive sleep apnea (OSA). MATERIALS AND METHODS: In retrospective manner, a total of 200 patients with OSA were randomly included. Group I contained 100 patients with OSA and no nocturia, and Group II included 100 patients with OSA and nocturia. Bivariate logistic analyses were used to identify variables most likely to contribute to nocturia. Multivariate logistic regression of age, waist circumference, STOP score (Snore, Tired, Obstruction and Pressure), and Apnea–Hypopnea Index (AHI) was performed to evaluate predictors of nocturia. Statistical significance was defined as P < 0.05. RESULTS: Median nocturia episodes were 2.2 in Group II. Patients were younger in Group I, with a mean age of 45 vs 50 years (P = 0.008). Mean BMI of 30 was similar in both groups, but there were more overweight patients in Group II (28% vs 18%). AHI approached significance between groups—18 vs 23 in group I and II, respectively (P = 0.071). In multivariate analysis, age over 70 years and moderate AHI were statistically significant predictors of nocturia (coefficients 0.6 and –0.2 with P = 0.003 and 0.03, respectively). CONCLUSIONS: This study identifies age and AHI score as predictors of nocturia in patients with OSA. This may indicate the usefulness of incorporating nocturia in the screening of patients with OSA. Future studies are needed to further evaluate mechanism of action, clinical significance, and effect of treatment for nocturia in patients with OSA.