Association between frailty and detrusor overactivity with detrusor underactivity in older women

PURPOSE: While detrusor overactivity (DO) with detrusor underactivity (DU) (DO-DU) has been described as typical of aging, the pathogenesis of DO-DU is highly multifactorial, and often thought to involve medical conditions beyond the urinary tract. We aimed to explore potential associations between idiopathic DO-DU and frailty in older women after accounting for age. METHODS: The design of the study is a cross-sectional single-center study, in an outpatient urodynamic unit specializing in geriatrics. Participants are consecutive female patients aged ≥65 years without contributory neurological conditions or bladder outlet obstruction who completed a comprehensive geriatric assessment followed by urodynamic evaluation from 2015 to 2019. Participants were categorized as having DO, DU, combined DO-DU, or a negative study. Multinomial logistic regression analysis was used to assess the relationship between urodynamic outcomes and frailty, as quantified using the Frailty index (FI). RESULTS: Ninety-five patients were included (median age 78 [interquartile range: 70-83] years), among whom 29% had combined DO-DU. The median FI score was 0.27 (0.2-0.32) (5-12). A higher FI was associated with significantly greater age-adjusted odds of DO-DU when either DU or subjects with a negative urodynamic assessment were used as the reference group. Age was not significantly associated with DO-DU across all multivariable analyses. CONCLUSION: A higher FI was associated with an increased likelihood of DO-DU, which could not be attributed to the effect of age alone. The pathogenesis of DO-DU is likely more complex than chronological aging in and of itself and merits further study.