Evaluation of Factors Influencing the Natural History of Nocturia in Elderly Subjects: Results of the Fujiwara-kyo Study

Purpose: We evaluated the natural history of nocturia and determined factors influencing the incidence or remission of nocturia. Materials and Methods: Study subjects were 4,427 volunteers 65 years old or older who participated in the Fujiwara-kyo Study. The nocturia prevalence was assessed at baseline and 1 year later. Nocturia incidence and remission rates were calculated and factors influencing these results were evaluated based on characteristics, including gender, age, body mass index, HbA1c, creatinine clearance, life style, comorbidities, depressive status, metabolic syndrome and voiding symptoms. Independent factors were determined by multivariate analysis. Results: Of the 4,427 subjects 3,685 provided complete replies to self-administered questionnaires at baseline and 1 year later. The prevalence of nocturia at baseline and 1 year later was 47.0% and 50.3%, and nocturia incidence and remission rates were 20.0% and 15.4%, respectively. Male gender, high body mass index, voiding symptom deterioration and new onset overactive bladder were independent factors associated with the nocturia incidence. Male gender, sum of the voiding symptoms, age and new onset overactive bladder were independent negative factors associated with nocturia remission. Conclusions: The prevalence of nocturia worsened with time, although nocturia in older subjects progressed dynamically. Male gender, age, body mass index, sum of voiding symptoms, voiding symptom deterioration and new onset overactive bladder influence the natural history of nocturia.