Nocturia has been associated with many comorbidities including cardiovascular diseases (CVD), and endocrine disorders. It has also been associated with chronic illnesses, such as chronic respiratory disease, neurological disease, and malignancy. Considering its associations with these many chronic comorbid conditions, several studies have reported a relationship between nocturia and mortality. However, related evidence in the literature is limited. The National Health and Nutrition Examination Survey (NHANES), a nationally representative population-based sample of the United States, was conducted by the National Center for Health Statistics of the Centers for Disease Control and Prevention. To date, only a few studies have investigated nocturia [1] or its association with mortality using NHANES data [2]. Only one study reported an association between nocturia and mortality risk using NHANES III 1988–1994, but the data used is about 30 years old [2]. Therefore, we investigated the relationship between nocturia and mortality risk in the United States using the NHANES data collected between 2005 and 2010.

Data were obtained from the NHANES 2005-2010. Mortality data were obtained by linking the primary database to death certificate data found in the National Death Index with mortality follow-up up to December 31, 2015. Nocturia was defined based on symptoms reported in the symptom questionnaire. We categorized patients into two groups: mild nocturia (2–3 voids/night) and moderate-to severe nocturia (≥4 voids/night). We estimated hazard ratios (HR) using multiple Cox proportional hazard regression analyses to investigate the effect of nocturia on all-cause mortality and CVD mortality. Moreover, considering the heterogeneity of the confounding variables according to nocturia, we conducted subgroup analysis with propensity score matching data (1:1 matching).

This study included 9,892 adults (4,758 men, 5,134 women). Nocturia occurred in 3,314 individuals (33.5%). Nocturia was more common in older individuals, women, smokers, and those with higher BMI and metabolic diseases. In addition, the prevalence of CVD was significantly higher in those with nocturia at the baseline survey. In the follow-up data up to 2015, adults with nocturia showed a significantly higher incidence of all-cause and CVD mortality than those without nocturia.
Kaplan-Meier survival curves revealed a significantly higher rate of all-cause mortality and CVD mortality in participants with nocturia than in those without nocturia. In the multiple Cox regression analysis, nocturia was significantly associated with all-cause mortality (HR: 1.23, 95%CI: 1.10–1.39, p<0.001) and CVD mortality (HR 1.55, 95%CI: 1.19–2.01, p=0.001). Mild and moderate-to-severe nocturia were both significantly associated with all-cause mortality (HR 1.17, 95%CI: 1.03–1.32, p=0.014; HR 1.67, 95%CI: 1.36–2.06, p<0.001, respectively) and CVD mortality (HR 1.49, 95%CI: 1.14–1.96, p=0.004; HR 1.90, 95%CI: 1.20–2.99, p=0.006, respectively). Considering the heterogeneity of the participants with nocturia, additional analysis was performed using 1:1 propensity score matching. With propensity score matching, nocturia was still significantly associated with all-cause mortality (HR 1.25, 95%CI: 1.10–1.41, p<0.001) and CVD mortality (HR 1.58, 95%CI: 1.2–2.07, p=0.001). Mild and moderate-to-severe nocturia were significantly associated with all-cause mortality (HR 1.18, 95%CI: 1.04–1.34, p=0.012; HR 1.69, 95%CI: 1.37–2.09, p<0.001, respectively) and CVD mortality (HR 1.52, 95%CI: 1.15–2.02, p=0.004; HR 1.94, 95%CI: 1.23–3.08, p=0.005, respectively).
In subgroup analysis according to sex, nocturia was significantly associated with all-cause mortality and CVD mortality in men. In women, moderate to severe nocturia was significantly associated with all-cause mortality and CVD mortality. In subgroup analysis according to cardio-metabolic diseases, nocturia was associated with CVD mortality in patients with diabetes mellitus, hypertension, dyslipidemia or CVD at baseline. In subgroup analysis of patients without diabetes mellitus, hypertension or CVD, nocturia was significantly associated with all-cause mortality.

Our population-based study demonstrated that mortality was significantly associated with mild and moderate-to-severe nocturia in men and women after adjusting for major confounding factors. Our study also showed that CVD mortality was associated with nocturia in a dose-dependent manner.

Our study provides strong support for the previously established relationship between nocturia and mortality.

Trends and prevalence of nocturia among US adults, 2005-2016. Int Urol Nephrol 2020;52:805-13.
Association of nocturia and mortality: results from the Third National Health and Nutrition Examination Survey. J Urol 2011;185:571-7.

Continence 2S2 (2022) 100337
DOI: 10.1016/j.cont.2022.100337