Urinary incontinence (UI) is defined as any involuntary leakage of urine and can be categorised into stress urinary incontinence (SUI), overactive bladder (OAB), or mixed urinary incontinence (MUI). Urinary incontinence is a common complaint with prevalence increasing with age and women being disproportionately affected. It has negative impact on the quality of a person’s life as well as carrying a large economic burden [1].
Diagnosis and categorisation of UI is essential to initiate the correct treatment, however, there is no standardised method. Common practises involve history taking, completion of a three-day bladder diary, and urodynamic evaluation. Some studies describe urodynamics (UDS) as the “gold-standard” for the assessment of UI but this is controversial. UDS does not always reproduce a patient’s symptoms, and is also an invasive, expensive, and time-consuming test [2]. There have been numerous validated symptom questionnaires developed for the assessment of urinary symptoms, many to be used for specific patient groups. Self-assessment questionnaires are tools for use in research as well as in clinical practice. The bladder self-assessment questionnaire (BSAQ) and the overactive bladder-V8 questionnaire (OAB-V8) are two validated self-assessment questionnaires for women with UI. OAB-V8 focuses on OAB exclusively, whereas B-SAQ covers a wider range of urinary symptoms combining OAB and SUI.
In this study we aim to establish whether there is a correlation between self-assessment questionnaire scores, using BSAQ and OAB-V8, and markers of severity on urodynamics in women with UI associated with OAB and proven detrusor overactivity. We used “first desire to void” (FDV) and maximum cystometric capacity (MCC) as parameters of severity previously described [3]. We expect that higher symptom scores should correspond to an earlier FDV and a lower volume MCC in women with clinical OAB and proven detrusor overactivity (DO) on urodynamic testing.

Data was collected from twenty-one women who were recruited as part of an ongoing study on women with OAB Ethics; A5-2: 10/H0805/51, IRAS number: 474470). Women with OAB were identified based on clinical symptoms and a three-day bladder diary. Women who did not respond to conservative treatment were recruited to our study following urodynamic investigation. Participants were asked to complete validated self-assessment questionnaires (BSAQ and OAB-V8). We used the Spearman correlation co-efficient to correlate the BSAQ and OAB scores with urodynamic parameters. We calculated p-values to establish whether correlations between patients reported symptoms scores, FDV and MCC, were statistically significant. Although “first desire to void” (FDV) can be subject to misinterpretation due to the patient’s first perception of saline loading, MCC was purposefully chosen as the most reproducible parameter of severity shown on UDS.

We found that there was a weak negative correlation between BSAQ scores (mean= 19) and FDV (mean= 159ml) (Spearman correlation coefficient: -0.08, p= 1), and we found a strong negative correlation between BSAQ and MCC (mean= 422ml) (Spearman correlation coefficient= -1, p=1) but with no statistical significance for either.
There was a weak positive correlation between OAB-V8 scores (mean= 28) and FDV (Spearman correlation coefficient= 0.11, p=1) and a strong positive correlation between OAB-V8 scores and MCC (Spearman correlation coefficient= 0.99, p=0.3), however, again with no statistical significance.

Validated questionnaires BSAQ and OAB-V8 have been proven to identify women with overactive bladder. Higher scores would suggest a more severe clinical presentation. Previous studies have shown that OAB severity positively correlates with an earlier first desire to void and a smaller maximum cystometric capacity (MCC) on UDS [3]. In the current study, BSAQ scores appeared to correlate better with parameters of severity on UDS when compared with OAB-V8, however none of the outcomes reached statistical significance. Our results showed a strong negative correlation between BSAQ scores and MCC, which is in line with more severe OAB. However, the exact opposite, a strong positive correlation, was demonstrated between OAB-V8 scores and MCC. A possible explanation could be that the same level of symptoms may impact two individuals differently. The OAB-V8 questionnaire does not include an assessment of quality of life, or a "bother score", whereas the BSAQ questionnaire does.

The present study highlights some of the challenges in the self-assessment of an individual’s urinary symptoms. Interestingly, BSAQ scores appeared to correlate better with urodynamic parameters of severity in OAB, despite being a tool designed for mixed UI, when compared to OAB-V8. However, none of the outcomes showed correlations that reached statistical significance. Validated symptom self-assessment questionnaires play an important role as screening tools, however, the value of their scores as an indication of disease severity is questionable.

Milsom I, Abrams P, Cardozo L, et al. How Widespread are the symptoms of overactive bladder and how are they managed? A population-based prevalence study. BJU Int 2001; 87: 760-766
Martin JL, Williams KS, Sutton AJ, Abrams KR, Assassa RP. Systematic review and meta-analysis of methods of diagnostic assessment for urinary incontinence. Neurourol Urodyn. 2006;25(7):674-83; discussion 84.
Ilias Giarenis , Martino Zacchè, Dudley Robinson, Linda Cardozo. Is there any association between urodynamic variables and severity of overactive bladder in women with idiopathic detrusor overactivity?. Neurourol Urodyn. 2017 Mar;36(3):780-783.doi: 10.1002/nau.23023. Epub 2016 Apr 19