The predictive value of pre-treatment cystometry in the outcome of women with mixed incontinence treated with duloxetine

Objectives

Whilst auditing the results of women treated with duloxetine, it was noted that some women with mixed urodynamic stress incontinence (USI) and detrusor overactivity (DO) reported worsening of their incontinence. Duloxetine works by increasing urethral resistance and may alter voiding function. Worsening voiding may result in worsening irritative symptoms. The aim of our study was to assess whether pre-treatment pressure flow studies predicted which women with mixed USI and DO became worse after treatment with duloxetine.

Study design

Women were recruited from our one-stop urogynaecology clinic. All women complained of troublesome mixed urinary symptoms with moderate or severe stress incontinence. Their initial assessment included a detailed history, a physical examination, a 3-day urinary diary, King's Quality of Life questionnaire and filling cystometry.

Results

Fifty seven women were recruited. Thirty (52%) women recorded an improvement in their patient global impression of improvement (PGI-I) score; 18 (32%) recorded no change and nine (16%) women reported worsening bladder symptoms. Pressure flow studies of women who recorded a worsening of their incontinence were compared to those women who recorded no change or an improvement of their incontinence. The maximum flow rate (p = 0.78), average flow rate (p = 0.61), bladder capacity (p = 0.14), detrusor pressure at maximum flow (p = 0.68) and volume voided (0.66) showed no statistical difference when the two groups were compared. The pre-treatment voiding time (p = 0.04) was statistically longer in women who got worse following treatment with duloxetine.

Conclusion

Pre-treatment pressure flow studies may be useful in predicting the outcome of treatment with duloxetine. Women who report worsening of their incontinence are more likely to have a longer voiding time compared to women who do not report worsening. Hence a prolonged voiding time may predict a poorer outcome for women treated with duloxetine.