There is currently no consensus on outcome reporting, or a core outcome set, for trials evaluating the pharmacological management of neurogenic overactive bladder. As determined in previous gynaecological and urological reviews, a wide variation in outcome reporting leads to heterogeneity between trials and hinders the quality of meta-analyses. (1) (2)

This study aimed to evaluate outcome and outcome measure reporting in randomised control trials (RCTs), assessing pharmacological interventions for neurogenic overactive bladder in adults. In addition we evaluated the quality of the eligible RCTs.

The search methodology and strategy were conducted in accordance with PRISMA guidelines. A systematic literature search of Embase, MEDLINE and the Cochrane CENTRAL databases was conducted from inception to October 2020 using Medical Subject Headings (MeSH) as follows: “Overactive Bladder”, “Urinary urgency”, “Urge Incontinence”, “Urgency Incontinence”, “Neuropathic”, “Neurogenic”.

Our search yielded 588 results. Titles and abstracts were initially screened and full texts assessed for eligibility. Eligibly trials’ references were reviewed, in addition to hand searching which found 19 more eligible articles. Predetermined eligibility criteria included: randomised controlled trials, adult participants and written in English language. Non randomised trials and secondary analysis studies were excluded. A total of forty two trials were included in the analysis, as seen in Figure 1.

Outcomes, outcome measures, and study characteristics were systematically extracted and grouped in a structured inventory. The outcomes were then grouped into outcome domains and then more broadly into themes according to COMET guidance (3).

Methodological quality and outcome reporting quality were assessed using the JADAD and MOMENT criteria. A Spearman’s rho correlation coefficient was calculated to assess the univariate association between the MOMENT score (dependent variable) and the JADAD, year of publication, the impact factor of the journal, and journal type (independent variables).

Forty-two trials were included, with a total of 4617 patients. Included trials reported 290 outcomes and 80 outcome measures. The three most frequently reported outcomes were “Maximum Cystometric Capacity”, “24 hours Incontinence Frequency”, and “Quality of Life”. There was significant variation in the use of outcome measures, with two domains, “Lower Urinary Tract Symptoms” and “Patient-Reported Outcomes”, using 16 or more measures. 

The median MOMENT score was 4.5 (Range: 2-6); the median JADAD score was 4 (Range: 2-5). Univariate analysis demonstrated a significant positive correlation between methodological reporting and outcome reporting quality (0.668, P<0.001), all other correlations were non-significant (p>0.05).

This systematic review demonstrates the heterogeneity in outcome and outcome measure reporting between RCTs. This is similar to previously reported urological and gynaecological systematic reviews. (1) (2) 

There was a significant range in the outcome reporting rate with “Maximum cystometric capacity” being reported in 40 trials compared to 89% of outcomes which were reported in 5 trials or fewer.

There is some evidence of consistency in reporting, particularly in high quality trials, with outcomes relating to “Urodynamics” and “Lower urinary tract symptoms” reported most frequently. However, the inventory of outcomes extracted in this review highlights that many trials target only a small number of stakeholders, primarily patients, and trials rarely report a set of outcomes relevant to all key stakeholders. 

Variation in reporting hinders the ability for synthesis of data, meta-analyses and comparisons between interventions. This contributes to research waste which ultimately can have a negative impact on clinical care. 

Furthermore, there is significant variation in outcome measures used across all trials. The category “Issues relating to quality of life and wellbeing” has 19 different outcome measures with only one measure, the “Incontinence Quality of Life Questionnaire” reported in more than three trials.

There is currently no recognised consensus on which outcomes and outcome measures should be used when evaluating the pharmacological interventions for neurogenic overactive bladder. This systematic review supports the development of a core outcome set to resolve the highlighted issues regarding lack of standardisation and heterogeneity. This will promote standardised and consistent outcome reporting to facilitate data synthesis.

Before the process of developing a core outcome set has been finalised we propose the use of an interim set of outcomes. This is based on the most common domains and outcomes in this review: Urodynamics (“Maximum cystometric capacity”, “Detrusor Compliance”), Lower urinary tract symptoms (“24 Hour Incontinence Episode Frequency”, “Frequency of voiding per 24 hours”) and Other complications (“Headache”, “Muscle Weakness”). Use of this interim set will facilitate the inclusion of data from existing trials in any future meta-analyses. We also recommend that each of these outcomes is assessed with a validated measure and the outcome measure is explicitly specified in the published text. 

Our next step in the development of a core outcome set will be to conduct Delphi surveys to ensure outcomes relevant to all key stakeholders are represented in a consensus-based core outcome set.

Doumouchtsis SK, Pookarnjanamorakot P, Durnea C, Zini M, Elfituri A, Haddad JM, et al. A systematic review on outcome reporting in randomised controlled trials on surgical interventions for female stress urinary incontinence: a call to develop a core outcome set. BJOG Int J Obstet Gynaecol. 2019;126(12):1417–22.
Ghai V, Subramanian V, Jan H, Pergialiotis V, Thakar R, Doumouchtsis SK. A systematic review on reported outcomes and outcome measures in female idiopathic chronic pelvic pain for the development of a core outcome set. BJOG Int J Obstet Gynaecol [Internet]. 2020 [cited 2020 Dec 11];n/a(n/a). Available from: https://obgyn.onlinelibrary.wiley.com/doi/abs/10.1111/1471-0528.16412
Williamson, P. R. et al. (2017) ‘The COMET Handbook: version 1.0’, Trials, 18(3), p. 280. doi: 10.1186/s13063-017-1978-4.