Cost, resource utilization, and treatment-taking behaviors among patients with OAB initiating combination mirabegron and antimuscarinic therapy in the US

Aims:

To estimate costs, number of encounters, and adherence and persistence, among overactive bladder (OAB) patients initiating mirabegron (MIRA) and antimuscarinic (AM) combination therapy.

Methods:

In this retrospective cohort study using US claims data, incident combination therapy users (identification period: April 2018–March 2019) were followed for one year from first observed combination therapy fill (index) and stratified into four treatment pathways based on subsequent treatments used: continued combination therapy, switched to monotherapy, discontinued combination therapy or transitioned to OAB procedures (e.g., onabotulinumtoxinA injection). Outcomes were all-cause and OAB-related healthcare per-patient-per-month (PPPM) costs, number of encounters, treatment persistence and adherence. The cohort was weighted to align with the age distribution of the population of interest.

Results:

Patients (n=761) were 69% female; mean age was 67.8 years. Median (interquartile range [IQR]) all-cause PPPM costs ranged from $1,432 ($785, $2,914) for the combination therapy group to $2,335 ($1,482, $5,152) for the procedures group. OAB-related costs were lowest for the discontinuers ($362 [$222, $522]) and highest for those receiving procedures ($810; [$512, $1,433]). The median (IQR) PPPM number of OAB-related outpatient services encounters was 0.2 (0.1, 0.3; similar across treatment pathway groups). Treatment persistence was 167 (83, 300) days; adherence through day 365 was 26%.

Conclusions:

Monthly all-cause healthcare costs were similar among all patients except for those that transitioned to receive an OAB procedure, which was associated with higher costs. Persistence on combination therapy was similar to published persistence estimates for MIRA monotherapy and was potentially higher than published reports of AM persistence, though adherence may be lower.