Abstract
Co-existent overactive-underactive bladder (COUB) is an area of highly unmet medical need, and epidemiological information is lacking, especially in men. Therefore, to illuminate the epidemiological characteristics of COUB in men, 3112 adult Japanese men responding to a nationwide internet survey on lower urinary tract symptoms (LUTS) were divided into COUB, overactive bladder (OAB) alone, underactive bladder (UAB) alone, and non-OAB/UAB groups based on the OAB symptom score and the International Continence Society-Working Group definition of UAB. We assessed each group's prevalence and health-related quality of life (HRQOL) and explored predictors of COUB as well as OAB and UAB using multinomial logistic regression analysis. The prevalences of COUB, OAB alone, and UAB alone were 4.3%, 9.6%, and 5.0%, respectively, and increased significantly with age. The proportions of COUB in OAB and UAB overall were 31.1% and 46.6%, respectively, but showed no significant increase with age. The proportion of participants experiencing an impact on their HRQOL was highest in the COUB group. A multinomial logistic regression analysis revealed that COUB and OAB alone shared predictive factors. The presence of COUB has a considerable impact on HRQOL and should be kept in mind when managing LUTS in men.