A non-interventional cross-sectional re-contact study investigating the relationship between overactive bladder and frailty in older adults in Japan

BACKGROUND: Increasing age is associated with frailty and a higher prevalence of overactive bladder (OAB). Given the rapidly increasing proportion of older adults in Japan, a better understanding of the relationship between frailty and OAB is needed to inform future healthcare planning. This study assessed the association between frailty and OAB in older adults in Japan and evaluated the impact on their health-related quality of life (HRQoL). METHODS: This was a cross-sectional re-contact study of respondents who previously completed the National Health and Wellness Survey 2018 in Japan. Participants were aged ≥65 years and Japanese speakers and readers. As part of a customized online survey, participants were screened for frailty using the Kihon Checklist (frail = scores ≥8 points) and OAB using the overactive bladder symptom score (OAB = total score ≥ 3 points and ≥ 2 points on question 3). The primary endpoint was the odds ratio of frailty in older adults with and without OAB assessed using a multivariable logistic regression model. Secondary endpoints were the prevalence rates of OAB and frailty. Exploratory endpoints assessed HRQoL using the Medical Outcomes Study 12-Item Short Form Survey Instrument version 2 (SF-12v2). RESULTS: Overall, 2953 participants were included: 150 (5.1%) were frail OAB, 416 (14.1%) non-frail OAB, 287 (9.7%) frail non-OAB, and 2100 (71.1%) non-frail non-OAB. There was a statistically significant correlation between frailty and OAB demonstrated by an adjusted odds ratio (95% CI) of 2.78 (2.18–3.54; p < 0.001). The prevalence (95% CI) of OAB was 34.3% (29.9–38.8) in frail and 16.5% (15.1–18.0) in non-frail older adults; the prevalence of frailty was 26.5% (22.9–30.1) and 12.0% (10.7–13.3) in older adults with and without OAB. HRQoL was assessed in 150 participants per group. The adjusted HRQoL analyses showed significantly lower scores in participants who were frail OAB vs. frail non-OAB for most of the SF-12v2 scores/sub-component scores. CONCLUSIONS: These data highlight the statistically significant positive correlation between frailty and OAB among older adults in Japan and may provide valuable information on the burden of OAB and frailty on older adults to healthcare professionals when considering future healthcare planning. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-022-02756-7.