Background: This study evaluated the clinical outcomes and economic results of transdermal oxybutynin compared to fesoterodine, tolterodine, solifenacin, oxybutynin, trospium chloride, and mirabegron for overactive bladder syndrome in Spain. Materials and Methods:A Markov model was built with monthly cycles for a 5-year time frame. The model reflected clinical events, discontinuation, dose scaling and change in treatment according to actual clinical practice. Based on experts' opinion and the literature, the use of resources and Spanish costs were incorporated into the model. The measure of efficiency used was the cost per quality-adjusted life year (QALY) gained. The economic evaluation was performed from the perspective of the Spanish healthcare system, discounting costs (€2017) and effects at 3%. The robustness of the results was validated with a deterministic and probabilistic sensitivity analysis. Results:After a year, transdermal oxybutynin was seen to have greater persistence deriving from its better risk/benefit balance compared to muscarinic antagonists and mirabegron (55% transdermal oxybutynin, 33% mirabegron, 25% tolterodine, 27% fesoterodine, 25% solifenacin, 23% trospium chloride and 17% oxybutynin). At 5-years, better persistence resulted in improvements in QALY gained by transdermal oxybutynin of 0.050, 0.040, 0.039, 0.038, 0.034 and 0.010 compared to oxybutynin, fesoterodine, solifenacin, trospium chloride, tolterodine and mirabegron, respectively. The incremental cost-effectiveness ratio of transdermal oxybutynin ranged from €1313.96 per QALY gained compared to fesoterodine to €14 101.57 per QALY gained compared to trospium chloride. Conclusions: Kentera ® (transdermal oxybutynin) is a cost-effective treatment in overactive bladder syndrome compared to muscarinic antagonists and mirabegron. Keywords: idiopathic overactive bladder, oxybutynin transdermal patch, cost-effectiveness, persistence, mirabegron, oral muscarinic antagonists JHEOR Crespo C, et al. 195 JHEOR 2018;5(2):194-205 | www.jheor.org BACKGROUND Disease BurdenOveractive bladder (OAB) syndrome is defined by the presence of urinary urgency, with or without urge urinary incontinence (UUI), often accompanied by urinary frequency and nocturia. 1 It is estimated that there are approximately 1.5 million people with OAB in Spain 2 ; however, only 16.7% of patients with OAB receive treatment. 3 OAB has a significant negative impact on the quality of life (QoL) of patients, their family members and their caregivers, since it affects social function, sexual function, interpersonal relationships and work life. 1,4 In addition, UUI has been associated with an increase in the use of resources and a decrease in the productive capacity of working-age patients. 5,6 Crespo C, et al. 203JHEOR 2018;5(2):194-205 | www.jheor.org information on the use of resources and costs. Thus, an estimate with real cost and effectiveness data could be prepared. CONCLUSIONSOXY-TDS led to more QALYs gained, due to its persistence and tolerability, and was a highly cost...