Ice Water Test Unmasks Detrusor Overactivity in Apparently Normal Conventional Cystometry

To evaluate the diagnostic value of the ice water test (IWT) in unmasking detrusor overactivity (DO) in patients with lower urinary tract symptoms (LUTS) who do not exhibit DO during conventional filling cystometry and to characterize this specific patient population.

In this observational cohort study, from April 2021 to December 2023, patients with LUTS but no DO in same-session repeat conventional filling cystometry were additionally evaluated using the IWT. All participants underwent standardized urodynamic investigations following International Continence Society guidelines.

The primary outcome was the presence of DO during the IWT. Demographic and clinical factors associated with DO were analyzed using mixed-effects logistic regression models.

In 529 UDIs of 451 patients (63 patients had more than one urodynamic investigation (UDI)) without DO in conventional filling cystometry, the IWT revealed DO in 51% (229/451). Detection was more frequent in patients with an underlying neurological disorder (53% vs 34%, p = 0.004), males (57% vs 42%, p = 0.007), and those using antimuscarinics (67% vs 43%, p < 0.001) or being treated with intradetrusor onabotulinumtoxinA injections in the past year (66% vs 46%, p = 0.002). These variables, along with increasing age, were independent predictors in a multivariable analysis.

In patients with LUTS but no DO on conventional filling cystometry, the IWT might reveal DO in approximately half of the cases. This underscores the diagnostic value of the IWT in both patients with neurological and nonneurological conditions and leads to a better understanding of LUTS-causing pathophysiology.