Comparative Neoplasm Risk of Mirabegron and Antimuscarinic Therapy in Overactive Bladder: A Multicenter Target Trial Emulation

Background/Aims: Mirabegron, a selective β3-adrenergic receptor agonist used to treat overactive bladder (OAB), can promote adipose tissue browning and alter systemic metabolism, raising interest in its potential relationship with cancer development. However, clinical evidence regarding cancer risk remains limited and inconsistent. We compared the risks of obesity-related and site-specific cancers between patients with OAB initiating mirabegron and those initiating antimuscarinic medications.

Methods

We conducted a multicenter emulated target trial using the TriNetX Global Collaborative Network. Adults aged ≥20 years with OAB or related symptoms who newly initiated mirabegron or an antimuscarinic medication were included using a new-user, active-comparator design. Patients with pre-existing malignancy were excluded. Propensity score matching was performed 1:1, and a 1-year lag period after treatment initiation was applied for cancer outcomes to reduce potential reverse causation from occult malignancy. Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) under an intention-to-treat analog.