Leakage plus detrusor overactivity may have clinical value

Dr. Smith's statement was based on findings from an exploratory study that included 67 women with urge incontinence of non-neurogenic etiology, of whom 42 had urodynamic evidence of leakage and 15 did not. Comparisons between the two study groups showed that urgency, incontinence symptoms, and quality of life were worse among women with leakage compared with those without, and findings from multiple endpoints indicated that presence of leakage was associated with decreased outlet resistance. The study also found that among women with leakage, the detrusor pressure at the moment when leakage occurred was lower in those with subjectively reported stress urinary incontinence (SUI) plus urge urinary incontinence (UUI) versus in those with UUI only.

"Currently, there is no urodynamics term that describes leakage accompanying DO," said Dr. Smith, assistant professor of urology in surgery at the University of Pennsylvania School of Medicine, Philadelphia. "Our findings suggest that the pressure at which it occurs may predict symptom severity and outlet resistance, and on that basis, that it should be added to standard urodynamic terminology.

The patients included in the study were identified from a retrospective review of patients who underwent videourodynamics over a recent 12-month period. Among a total of 222 patients, 78 were identified who had urgency or UUI reported on questionnaire and who had DO on urodynamics. The 62 patients included in the study represented those left after excluding patients with neurogenic bladder or obstruction, and all were women.

The groups of DO patients with and without leakage were compared for mean scores on various items from the Urogenital Distress Inventory (UDI-6), Symptom Severity Index, and a quality of life questionnaire.

Women with leakage fare worse

The results showed women with DO plus leakage had significantly worse scores for urgency, UUI symptom severity, and UUI bother than women with DO only, as well as a significantly higher (worse) mean quality of life score. The women with leakage also had worse scores for measures of SUI severity and SUI bother than their counterparts without leakage. While none of the differences between groups for the SUI outcomes achieved statistical significance, notable trends were appreciated.

"The finding of differences in urgency and urge incontinence between patients with and without leakage is somewhat intuitive. Our inability to find a statistically significant difference between the two groups in subjective symptoms of SUI may be due to lack of sufficient power, and so we are now repeating this evaluation in a larger sample size," Dr. Smith said.

Analyses of urodynamics parameters showed the presence of symptoms of SUI among women with leakage was associated with a lower DOLPP; mean DOLPP was 18 cm H₂O among the women with leakage and both SUI and UUI versus 31 cm H₂O among those with pure UUI. Other comparisons between women with leakage and those without showed urodynamic SUI was more common among those with leakage (43% vs. 27%), and mean maximum urethral closure pressure (MUCP) was lower (63 cm H₂O vs. 72 cm H₂O), as was detrusor pressure at peak flow (voiding pressure) (27 cm H₂O vs. 42 cm H₂O). Only the between-group difference in detrusor pressure at peak flow was statistically significant.

"These differences between the women with and without leakage indicate that leakage with DO may be associated with lower outlet resistance, and suggest that increasing outlet resistance may be a therapeutic target for eliminating leakage in women with overactive bladder and improving their quality of life," Dr. Smith said.