Drug utilization study of mirabegron (Betmiga) using real-world healthcare databases from the Netherlands, Spain, United Kingdom and Finland

Date of ISAC Approval: 
Lay Summary: 
Mirabegron is used to treat the symptoms of an overactive bladder. Use of mirabegron is not advised in patients with high blood pressure (hypertension) that is severe and not controlled by medication. In September 2015, a 'Dear Doctor' letter was sent to healthcare professionals in thirty EU countries to notify them of this advice. To test the effectiveness of this communication as a strategy to minimise risk, a study will be conducted on the use of mirabegron using routine healthcare data from the Netherlands, Spain, United Kingdom and Finland. Data from before and after the date of the 'Dear Doctor' letter will be used to quantify the proportion of patients prescribed mirabegron who have documented hypertension (controlled, uncontrolled and severe uncontrolled). The frequency of blood pressure measurements in hypertensive patients prescribed mirabegron will also be evaluated. The findings of this study will determine the impact of the 'Dear Doctor' letter in relation to appropriate and safe prescribing of mirabegron.
Technical Summary: 
The aim of this study is to determine the effectiveness of a 'Dear Doctor' communication highlighting a contraindication in use of mirabegron in patients with severe and uncontrolled hypertension. The objectives are to determine the proportion of patients newly-prescribed mirabegron who have documented hypertension (controlled, uncontrolled and severe uncontrolled), and to evaluate the frequency of blood pressure recording in mirabegron patients stratified by their hypertension status at the index date. A retrospective cohort design will be used, selecting patients initiating mirabegron treatment between 20th December 2012 and 31st December 2016. Patient time will be divided into periods of uninterrupted mirabegron use, and descriptive results will be presented pre- and post- dissemination of the 'Dear Doctor' letter. If adequate patient numbers are available, an interrupted time series design will be utilised to estimate incremental changes in hypertension status among mirabegron users in relation to time after the 'Dear Doctor' letter.
Health Outcomes to be Measured: 
Proportion of mirabegron initiators with hypertension; Frequency of blood pressure recording in mirabegron initiators.

Ms Helen Booth - Chief Investigator - CPRD
Mr Daniel Dedman - Collaborator - CPRD
Ms Helen Booth - Corresponding Applicant - CPRD