Comparative study of different combinations of mirabegron and antimuscarinics in treatment for overactive bladder syndrome in elderly patients.

Objectives: To compare the therapeutic efficacy, adverse events (AEs), and patient preference in elderly patients with overactive bladder (OAB) receiving different combinations of mirabegron and solifenacin.

Materials and methods: Elderly OAB patients received mirabegron 25 mg (M25) daily for 1 month (1M) followed by randomization to receive M25 (Group 1), mirabegron 50 mg (M50, Group 2), solifenacin 5 mg (S5, group 3); or M25 plus S5 (Group 4) for further 2 months. Efficacy and AEs were evaluated. At the end of 3M, patients' preferred option for future treatment was investigated.

Results: A total of 168 patients were enrolled, and 100 completed 3-month treatment. At 1M, all parameters improved significantly except postvoid residual (PVR), 23 (13.7%) patients had no symptom, 16 (9.5%) had no improvement, and 10 (6.0%) withdrew from the trial. Compared parameters at 3M with 1M revealed that quality of life, Patient's Perception of Bladder Condition scores, and voided volume improved significantly in group 1; the OAB Symptom Score (OABSS) increased in group 2; mean PVR and Global Response Assessment (GRA) deteriorated in group 3; and the OABSS and GRA improved in group 4. At 3M, the AEs prevalence increased significantly in group 3. Only 38.1% in group 4 preferred long-term usage of combination therapy.

Conclusion: M25 daily is effective and safe in treating elderly OAB patients. Dose escalation to 50 mg or shifting to S5 does not increase the therapeutic efficacy. Combining M25 with S5 provides better treatment efficacy but is associated with lower patient compliance than M25 alone.