The "Aberdeen Home Continence Stress Test": a novel objective assessment tool for female stress urinary incontinence

Abstract

Introduction and hypothesis: Clinical trials for stress urinary incontinence (SUI) require a robust, reliable, and responsive tool for objective assessment of SUI post-intervention. The Aberdeen Home Continence Stress Test (HCST) is a novel patient-reported objective assessment tool, aimed to be patient-friendly and reduce attrition rates by avoiding hospital appointments and prolonged pad-wearing. We aim to describe the HCST for the first time and evaluate its reliability, diagnostic accuracy, and response to change.

Methods: A secondary analysis of the Single-Incision Mini-Slings (SIMS) study (a prospective multicentre randomised control trial (RCT) comparing two surgical treatments of SUI was performed. In SIMS (n = 600 women), the objective outcome was assessed by the 24-h pad test, while the patient-reported success rates were assessed using the Patient Global Impression of Improvement (PGI-I) at 15 months, 2 years and 3 years post-randomisation. Participants were instructed to perform the HCST before and after the 24-h pad test. The HCST was analysed in relation to reliability, validity, and the relationship between the 24-h pad test and HCST results and finally with regard to its responsiveness to change in PGI-I. (Trial registration-number ISRCTN93264234, registration date 14/01/2014).

Results: Compared to the 24-h pad test, the sensitivity of the HCST ranged from 0.81-0.95, specificity was 0.76-0.79, negative predictive value was 0.96-0.99 and positive predictive value was 0.32-0.43. Reliability was indicated by high-performing Cronbach's alpha value (> 0.7). An improvement of ≥ 2 leakage groups on the HCST (for example from Large at baseline to Small leakage at follow-up) was strongly associated with patient-reported success on PGI-I (OR 4.38, 95% CI 2.31, 8.31).

Conclusions: The HCST is a valid and reliable patient-reported objective assessment tool that can be used for assessing SUI in surgical trials with good specificity, sensitivity, and consistency.

Keywords: Diagnostic accuracy; Incontinence; Measurement tool; Stress incontinence.