Triple Therapy with Tamsulosin, Dutasteride, and Imidafenacin for Benign Prostatic Hyperplasia in Patients with Overactive Bladder Symptoms Refractory to Tamsulosin: Subgroup Analyses of the DIrecT Study

Aim: To verify if the efficacy of the triple therapy with tamsulosin, dutasteride, and imidafenacin (TDI) is influenced by any background characteristics in patients with overactive bladder (OAB). Methods: A subanalysis of data from the DIrecT study was conducted. Superiority of TDI over tamsulosin and dutasteride in terms of efficacy based on the Overactive Bladder Symptom Score (OABSS), total International Prostate Symptom Score (IPSS), IPSS quality of life index, and postvoid residual (PVR) was evaluated in binary subgroups. Results: In the treatment groups, there was a significant interaction of total OABSS with testosterone level (≥4.8 vs. <4.8 ng/mL, p = 0.043) and PVR (≥20 vs. <20 mL, p = 0.018). For the total IPSS, no significant interaction was found except for the IPSS QOL index. For the IPSS QOL index, a significant interaction was found with testosterone level (≥4.8 vs. <4.8 ng/mL, p < 0.0001) as well as with total IPSS and total OABSS. For the PVR, no significant interaction was found except with total OABSS. Conclusions: Triple therapy with TDI is suggested to be a therapeutic option for benign prostatic hyperplasia in patients with residual OAB symptoms refractory to tamsulosin and in patients with various background characteristics regardless of severity of OAB symptoms. Trial Registry No. UMIN 000011980.