Nagahama Study: Nocturia predicts mortality

Nocturia is a risk factor for mortality, according to the results of the Nagahama Study, which boasts of a low incidence of missing data and high representation of the general population.

The investigators examined the association between nocturia and mortality using data obtained from the Nagahama Cohort Project, a longitudinal, general population cohort study. They measured nocturia using the International Prostate Symptom Score and obtained mortality data from the Basic Resident Register in Nagahama City. Cox proportional hazard models and time-varying covariates at baseline and 5-year follow-up were used to analyse the association between nocturia and death.

A total of 9,762 participants (median age, 56.8 years; 32.8 percent male) were included in the analysis. The prevalence rates of nocturnal voiding were 44.3 percent at 0 times, 39.1 percent at 1 time, 11.7 percent at 2 times, and 4.9 percent at ≥3 times. Of the participants, 263 died during the study period. Follow-up assessment was carried out 3,224 days after baseline.

Multivariable Cox proportional hazard regression analysis revealed a dose-dependent increase in mortality with nocturnal voiding frequency (hazard ratio [HR] for 1 time, 1.46, 95 percent confidence interval [CI], 1.02–2.09; HR for 2 times, 1.85, 95 percent CI, 1.23–2.77; HR for ≥3 times, 2.06, 95 percent CI, 1.28–3.32) in comparison with 0 times (p_trend=0.00084). Of note, the significant association persisted in the time-varying Cox proportional hazard regression (p_trend=0.0017).