Urodynamics is the study of the capacity and flow rate of urine of the urinary bladder. It is a key test used in the investigation of patients complaining of urinary incontinence, or lower urinary tract symptoms, or both.

It is well-known that several medical calculations and values are standardised and adjusted to different variables including age, sex, and ethnicity. Currently, there is no standardisation for urodynamic studies according to different variables. We investigated whether different factors may contribute to change in the  urodynamic studies.  This study also aimed to investigate the of several demographic and clinical factors on the development of urinary stress incontinence (USI), detrusor overactivity (DO), detrusor failure (DF), or a combination of these diagnoses, to identify any causal relationships.

This study is a retrospective single-centre cohort study. Patients who presented to the urogynaecology clinic and underwent urodynamic evaluation over a 3 month period between 01/06/21 -31/08/21 were included.

A total of 56 patients were identified during the study period. 12 patients were excluded as  no urodynamic studies reported  due to non-attendance and urinary infection.  44 patients were ultimately included in the study. For each case, medical notes were collected to ascertain demographic data, as well as the results of urodynamic investigations. Demographic data included age, ethnicity, body mass index (BMI), parity, and relevant comorbidities. Where data was missing, no imputation was made, and all analyses pertained to the remaining data sets.

44 patients were included in our study. The median participant age was 56 (21 – 87) years, mean BMI was 28.82 (SD 6.33), and mean parity was 1.55 (SD 0.87). 

The most prevalent urodynamic diagnosis was DO (34.1%) in our cohort. USI was identified in 29.5% of patients, DF in 6.8% and a mixed diagnosis in 4.5%. The remaining 11 patients had normal urodynamic studies.

On binary logistic regression, parity was a predictive factor for USI (p = 0.004), and age was a predictive factor for DF (p = 0.019). No statistically significant associations were found between bladder capacity and age, BMI, or parity.There was no relationship between BMI and urodynamic parameters among patients with urinary incontinence.

The results suggest that there are certainly some factors that are predictive of different urogynaecological diagnoses. Based on our results, an increase in parity resulted in an increased susceptibility to USI, and increasing age was related to the development of DF. 

According to previous literature age has been shown to influence urodynamic studies. Ageing is associated with decreased self-control, and an elevated prevalence of lower urinary tract symptoms in females (1). 

As of current, there is no standardisation with regards to urodynamic studies based on different factors such as age, gender, or ethnicity. Our results show that certain factors may influence urodynamic testing, and thus, normal parameters for different cohorts of individuals should be adjusted accordingly

This study is part of an initiative to enable future researchers to conduct studies on a large scale, to identify whether if it is warranted for urodynamic values to be standardised according to different demographic and clinical variables.

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A multicentre study of ethnicity and diagnosis of urinary incontinence. International Urogynaecology Journal; Jun 2017; vol. 28 (1)  Thiagamoorthy G.; Hunter J.E.; Cardozo L.; Robinson D.; Bray R.; Araklitis G.; Giarenis I.; Khullar V.
Relationship of urodynamic parameters and obesity in women with stress urinary incontinence. The Journal of reproductive medicine; Jul 2002; vol. 47 (no. 7); p. 559-563  Bai, Sang Wook; Kang, Ji Yong; Rha, Koon Ho; Lee, Moo Sang; Kim, Jeong Yeon; Park, Ki Hyun