Similar artefact susceptibility for water- and air-filled urodynamic systems: a non-inferiority randomised controlled trial

Abstract

Objectives

To determine whether air-filled systems (AFS) provide comparable urodynamic investigation (UDI) trace quality to water-filled systems (WFS), the recommended standard by the International Continence Society.

Patients and Methods

A total of 490 patients undergoing UDI from April 2021 to January 2022 were included in this non-inferiority randomised controlled trial. Eligible patients were female and male adults with neurogenic lower urinary tract dysfunction (NLUTD). Patients were allocated by block randomisation in a 1:1 ratio to undergo UDI using a WFS (n = 244) or an AFS (n = 246). The primary endpoint was artefact susceptibility evaluated by a ‘blinded’ assessor using a modified ‘Bristol UTraQ’ quality scoring scale ranging from 0 to 18, with higher scores indicating a better quality. A clinically meaningful non-inferiority margin was pre-specified as −2 points on the quality scoring scale (AFS-WFS).

Results

The median (interquartile range [IQR]) overall quality score was 14.5 (13.5–15.5) points for the WFS and 15.5 (14.5–16.5) points for the AFS. Inferiority of AFS could be rejected at the pre-specified non-inferiority margin (0.96, 95% confidence interval 0.68–1.25; P < 0.001). Artefacts were more frequent in WFS. Typical artefacts consisted of repeat rectal contractions, poor pressure transmission during cough test at empty bladder, and detrusor resting pressure outside of the physiological range at empty bladder.

Conclusions

Our results indicate that AFS are non-inferior to WFS regarding overall urodynamic trace quality in patients with NLUTD.