Does urodynamic verification of overactive bladder determine treatment success? Results from a randomized placebo-controlled study

To determine whether subjects with or with no detrusor overactivity (DO) determined by urodynamic assessment respond differently to treatment with the antimuscarinic agent tolterodine (extended release formulation, ER). Adult subjects with urinary frequency (average >= 8 voids/24 h) and urgency with or without urgency urinary incontinence (UUI) underwent urodynamic assessment and were stratified according to whether they had DO (positive urodynamics) or not (negative urodynamics). Subjects in each urodynamic stratum were randomized to receive tolterodine-ER (4 mg once daily) or placebo for 12 weeks. Diary cards were completed for 7 days before each study visit (at baseline, week 4, and week 12). The volume per void was recorded for 3 of the 7 days. The difference between the positive and negative urodynamic groups in mean change in volume voided between baseline and 12 weeks was 5.38 mL (95% CI, -93 mL to +15.71 mL). This difference is within the pre-stipulated range defined for equivalence (+/- 20 mL, P = 0.31). There was also no significant difference in the change from baseline to 12 weeks between the urodynamics groups in mean number of voids per day or UUI episodes. However, there was significant improvement in the treatment group compared with the placebo group, in the number of voids per 24 h (P = 0.003) and in the mean change in volume voided (P = 0.03), from baseline to 12 weeks, but not in UUI episodes (P = 0.35). Urodynamics status could not predict treatment outcomes between patients treated with tolterodine-ER or placebo. The results add support to evidence suggesting that urodynamic assessment is not a prerequisite for the treatment of overactive bladder (OAB). Therefore, we recommend that anticholinergic treatment may be initiated to patients with OAB symptoms without the need for urodynamics studies.