Understanding the effects on HR-QoL of treatment for overactive bladder: a detailed analysis of EQ-5D clinical trial data for mirabegron
Pavesi M, Devlin N, Hakimi Z, Nazir J, Herdman M, Hoyle C, Odeyemi I. J Med Econ. 2013 May 6. [Epub ahead of print]


Data Management Centre, European Consortium on Liver Failure, Hospital ClĂ­nic i Provincial, Barcelona, Spain.


Background: Analysis of EQ-5D data often focuses on changes in utility, ignoring valuable information from other parts of the instrument. Our objective was to explore how the utility index, EQ-5D profile, and EQ-VAS captured change in clinical trials of mirabegron, a new treatment for overactive bladder (OAB). Data: Data were pooled from three phase III clinical trials that investigated the efficacy and safety of mirabegron versus placebo. Tolterodine ER 4mg was included as an active control in one study: (1) placebo, mirabegron 50mg and 100mg, and tolterodine 4mg ER; (2) placebo, mirabegron 50mg and 100mg); (3) placebo, and mirabegron 25mg and 50mg. Data were collected at baseline, week 4, 8 and 12. Methods: Analyses were performed on full analysis and modified intention to treat (ITT) data sets using UK utilities. Analysis controlled for relevant patient characteristics. Analysis of Covariance identified changes from baseline at each time point in utilities and EQ-VAS. Areas Under the Curve were estimated to summarise intertemporal differences in effect. EQ-5D profile data were analysed using the Paretian Classification of Health Change. Results: In modified ITT analyses, mirabegron 50mg was superior to tolterodine 4mg in changes from baseline utilities after 12 weeks (p<0.05); similarly, AUC results showed mirabegron 50mg to be superior to tolterodine (p<0.05) and placebo (p<0.05) with the benefit already apparent at 4 weeks (p<0.05). EQ-VAS more consistently indicated superior outcomes: all three mirabegron doses showed statistically significant greater effectiveness compared to tolterodine at 12 weeks. Individual EQ-5D dimensions and the overall profile showed no significant differences between study arms. Conclusion: Mirabegron showed quicker and superior improvement in HR-QoL compared to tolterodine 4mg ER. A limitation of the study is that EQ-5D was a secondary outcome in the pivotal trials, which were not powered to measure differences on EQ-5D.