Does Urodynamic Stress Incontinence Increase After the Menopause?: Results from 2,994 Urodynamic Studies in Australian Women

Introduction and hypothesis: Most studies attempting to estimate the age-related prevalence of urinary incontinence (UI) have used questionnaires. In the present study we analysed a consecutive series of urodynamic test results to determine the distribution of the different types of UI in pre- and post-menopausal women. We hypothesised that the prevalence of urodynamic stress incontinence (USI) would be significantly greater in pre-menopausal than in post-menopausal women.

Methods: All women from a large tertiary urogynaecology department, who underwent urodynamic tests during the years 2000-2015 were included. Patient history and test results were collected. A sample size of 1,475 was calculated, based on the hypothesis that the prevalence of USI will be 20% larger in the pre- versus the post-menopausal group.

Results: A total of 2,994 women with UI on urodynamics were available. There was a significant difference between pre- and post-menopausal status for each of the three diagnoses: USI 483 (59.3%) versus 912 (41.8%), detrusor overactivity (DO) 125 (15.4%) versus 399 (18.3%) and USI with concomitant DO 206 (25.3%) versus 869 (39.9%). A bimodal pattern of age was seen in women with USI, with a peak in the 46-50 and 61-65 age group, before decreasing with age. DO generally increased with age. USI with concomitant DO increased steadily after the menopause, becoming the predominant type after the age of 66.

Conclusions: In this large cohort of women attending urodynamics, we have shown that USI is the predominant type of incontinence in pre-menopausal women; however, USI with concomitant DO increases after menopause, eventually predominating.