Treatment of refractory overactive bladder with OnabotulinumtoxinA vs PTNS: TROOP trial

We hypothesized that patients with refractory overactive bladder (rOAB) have similar improvement with percutaneous tibial nerve stimulation (PTNS) and OnabotulinumtoxinA (BTX).

This multicenter cohort study compared BTX and PTNS in women with rOAB. Baseline information included Overactive Bladder Questionnaire (OABq) short form, Urinary Distress Inventory-6 (UDI-6), and voiding diary. Primary outcome was cure, defined as "very much better" or "much better" on the Patient Global Impression of Improvement (PGII) AND a reduction in OABq symptom severity scale (SSS) ≥10 at 3 months after treatment. Assuming 80% power to detect a ten-point difference in OABq-SSS, 80 participants were required per group.

A total of 150 patients were enrolled; 97 completed 3 months of therapy and were included. At baseline, BTX patients had more detrusor overactivity (70% vs 40%, p = 0.025), urgency incontinence (UUI; OABq-SSS#6 4 vs 3, p = 0.02, SSS 65 vs 56, p = 0.04), but similar health-related quality of life (HRQL 49 vs 54, p = 0.28), voids (7 vs 8, p = 0.13), and UUI episodes (2 vs 2, p = 1.0). At 3 months, cure rates were similar: BTX 50% vs PTNS 44.2% (p = 0.56). Both groups had improved SSS (-37 vs -29, p = 0.08) and HRQL (31 vs 24, p = 0.14). Patients receiving BTX had a greater improvement in urgency (ΔOABq-SSS#2-3 vs -2; p = 0.02) and UUI (ΔOABq-SSS#6-2 vs -1; p = 0.02). No characteristics were predictive of cure.

BTX resulted in significantly greater improvement in urgency and UUI than PTNS, but no difference in success based on PGII and OABq-SSS, which may be due to a lack of power.