RESUMO
INTRODUCTION AND HYPOTHESIS: To determine if Onabotulinumtoxin A (Botox®) should be offered as a first-line therapy for the treatment of overactive bladder (OAB), even before prescribing anticholinergics. METHODS: We performed a cost-effectiveness analysis modeling the following clinical options: no treatment, non-selective anticholinergics, selective anticholinergics, and Botox®. The model timeframe was 2 years to allow Botox® reinjection and discontinuation of anticholinergics. Multiple efficacy levels included response improvement by < 50%, 50%, 75%, and 100%. Botox® reinjection was allowed at 6 months if < 50% efficacy. Botox® complications and anticholinergic side effects were noted. We modeled up to one medication switch. No crossover from Botox® to anticholinergics or vice versa was allowed, and failures remained with refractory untreated overactive bladder. Medical literature data were used for model parameter values. Costs are 2016 $US. RESULTS: Botox® costs more than non-selective anticholinergics and less than selective anticholinergics in models with and without refractory overactive bladder costs. Botox® had the highest effectiveness (1.763 quality-adjusted life years). Using incremental cost-effectiveness ratios, Botox® was found to be cost-effective in models with and without refractory costs ($12,428.75 and $14,437.01, respectively). In both models, Botox® cost less and was more effective than selective anticholinergics, which were "dominated." Over 2 years, subjects averaged 15.6 and 14.3 months on selective and non-selective anticholinergics, respectively, and patients averaged 2.2 Botox® injections. Model results were unchanged with variation of input parameter estimates in sensitivity analyses. CONCLUSIONS: Botox® is a cost-effective therapy for overactive bladder and should be further explored as a first-line option in the treatment paradigm.
