Efficacy of antimuscarinic therapy for overactive bladder with varying degrees of incontinence severity

Purpose: We analyze the efficacy of tolterodine extended release (ER) for overactive bladder in patients with severe incontinence. Materials and Methods: Patients with urinary frequency (8 micturitions or greater per 24 hours), urge incontinence (5 episodes or greater a week) and symptoms of overactive bladder for 6 months or greater were randomized to treatment with 4 mg tolterodine ER once daily or placebo for 12 weeks. Severe incontinence was defined as 21 episodes or greater per week at baseline. Changes in the number of incontinence episodes per week and micturition frequency after 12 weeks were compared between treatments. Results: A total of 986 patients were eligible for this post-hoc analysis. After 12 weeks tolterodine ER produced a significant absolute median reduction in incontinence episodes per week compared to placebo (9.0 vs 5.0, p <0.0001). For patients with severe incontinence at baseline median absolute and percentage reductions in incontinence episodes per week were significantly greater with tolterodine ER than placebo (21.0 vs 9.5, p <0.0001; 67.6% vs 29.8%, p = 0.022). Micturition frequency decreased (p <0.02) and volume voided per micturition (p <0.0001) increased significantly more with tolterodine ER compared with placebo in these patients. For patients with nonsevere incontinence at baseline median reductions in incontinence episodes per week were also significantly greater with tolterodine ER than placebo (6.0 vs 4.0, p <0.0001; 71.4% vs 38.5%, p = 0.026). Conclusions: Patients with more severe incontinence at baseline achieved greater absolute reductions in incontinence with tolterodine compared to those with less severe symptoms. The degree of improvement, as measured by percent change, was comparable across the entire range of baseline incontinence severity strata. Benefits of antimuscarinic therapy may be greater in these patients than previously reported.