The influence of nocturia on the quality of life.

Background: Previous studies identified an effect of nocturia (two or more micturitions per night) on quality of life. We hypothesize that nocturia indeed affect quality of life but that effect is mediated via sleep. Nocturia and sleep disturbances are clearly associated. To go to the toilet one has to wake up. Lack of sleep is associated with mood disorders, depression and an increase of sleeping during daytime, all of which implies a decrease of quality of life. Aim: To estimate the influence of nocturia on the quality of life in the Dutch adult population. Methods: A telephone survey on the prevalence of nocturia was held among a representative sample of 4721 Dutch respondents (response: N=2506: 53%). A written survey on the quality of life and nocturia was held among a weighed sample of 1000 respondents, all previous participants of the telephone survey (response: N=859: 86%). The questionnaire contained questions from the B-LUTS which includes questions on nocturia. Using questions from the RAND-36 respondents were asked about their physical functioning and mental health. Questions from the SWEL were used to ask about sleep disturbances. In addition, questions about socio demographic and health characteristics were asked. The data were analysed using covariance and multivariate regression analysis. Results: Respondents with nocturia had more sleep disturbances compared to other respondents. The regression model that included nocturia and confounders showed that respondents with nocturia scored lower on the quality of life scales compared to respondents without nocturia. This decreased to a non-significant difference after including sleep in the model. Therefore there is no direct effect of nocturia on quality of life, the effect is mediated by sleep. Conclusions: Nocturia is not a symptom that stands on its own. It is accompanied by poorer sleep and consequently by poorer quality of life. Patients with nocturia will probably already be known by their doctor because of other symptoms. It is worthwhile for doctors to routinely check whether or not patients who contact them for sleeping disorders have nocturia. In the Netherlands, this is especially true for older women with a poor health status since they are the most likely to suffer from nocturia. (aut. ref.