Establishing the diagnosis of urinary incontinence often requires technical procedures, such as urodynamic studies (UDS), which may be uncomfortable and time consuming, especially among elderly individuals. Efficient implementation is of utmost importance. The main objective of this study is to identify disparities between the outcomes of successive urodynamic studies conducted in sitting and standing positions, and to evaluate their concordance, as to potentially streamline the diagnostic workup for older adults with urinary incontinence.

The “Think Dry: Optimalisation of Diagnostic Process of Urinary Incontinence in Older People” study (NCT04094753) is a prospective observational cohort study aiming to create a short form of necessary technical investigations to diagnose and evaluate urinary incontinence. Inclusion criteria were age 65 years or older, and every type of urinary incontinence. Exclusion criteria were patients with an indwelling urinary catheter or performing clean intermittent catheterization. Of the 180 patients in the database, 102 patients received a sitting and standing UDS and were subsequently included in this secondary analysis. 

To compare both UDS, specific urodynamic parameters were recorded adherent to the standards written in the International Continence Society (ICS) report. (1) Each patient underwent two UDS, one conducted in the sitting position and the other in the standing position. The voiding phase was conducted in a seated position for both groups. The final diagnosis encompassing stress, urge or mixed incontinence was determined by the referring urologist who - apart from the UDS - had access to additional patient data such as clinical examination findings, medical history, voiding diaries and multiple questionnaires. Subsequently, an experienced urologist reviewed both UDS without knowledge of the previously established diagnosis. To assess the agreement between the final diagnosis and the diagnosis derived from retrospectively reviewed studies, a concordance analysis was undertaken employing Cohen’s Kappa coefficient. Statistical analysis was performed using Statistical Product and Service Solutions (SPSS) version 27.

Patient characteristic analysis showed a median age of 74 years (interquartile range (IQR) 70-78), with females representing 90.2% of the study population. The distribution among patient groups - based on the diagnosis - with stress, urge, or mixed incontinence was 40.2%, 30.4%, and 29.4% respectively. When comparing the urodynamic parameters between the sitting and standing position, a statistically significant difference was only seen in the post-void residual in the general study population. The subgroup analysis based on the final diagnosis can be seen in Table 1. When using a cut-off for the median to create age groups (74 years), no differences were found comparing the same urodynamic parameters.   

The concordance analysis - for finding agreements between the separately reviewed UDS sitting versus standing in relation with the final diagnosis - can be seen in Figure 1, with a subgroup analysis based on the final incontinence diagnosis. In the general study population, a kappa-value of 0.42 was computed for the agreement between the sitting UDS and final diagnosis compared to a higher kappa-value of 0.92 for the agreement between the standing position and final diagnosis.

Numerous statistically significant differences were seen in urodynamic parameters between the sitting and standing positions, also when doing a subanalysis categorized by diagnosis. However, these distinctions are within normal bounds, and the absolute differences remain within marginal ranges. Based on these specific individual urodynamic parameters, no relevant differences can be concluded between both sitting and standing UDS. 

However, an important clinical difference was seen when looking at the concordance analysis, comparing the final diagnosis with those based solely on the retrospectively reviewed sitting versus standing UDS. The analysis revealed only a moderate level of agreement on final diagnosis in the sitting position in contrast to a very high level of agreement if the patient was standing. Additional subgroup analyses, focusing on specific types of incontinence, yielded consistent outcomes.

Our findings suggest that UDS conducted on elderly patients with urinary incontinence while standing may provide a higher diagnostic concordance. This could potentially allow the omission of additional testing in the sitting position, thereby leading to reduced discomfort and greater efficiency. However, this may be influenced by the order of testing, suggesting a potential learning effect. A randomized testing sequence is recommended for future research to confirm these findings.

Rosier P.F.W.M., Schaefer W., Lose G., Goldman H.B., Guralnick M., Eustice S., Dickinson T., Hashim H., International continence society good urodynamic practices and terms 2016: Urodynamics, uroflowmetry, cystometry, and pressure-flow study, Neurourol. Urodyn., 36 (5) (2017), pp. 1243-1260, doi: 10.1002/nau.23124.