[1] UCL, Inst Hlth Informat, Fac Populat Hlth Sci, London, England
[2] Univ Coll London Hosp, Clin Res Informat Unit, London, England
[3] Univ Coll London Hosp, Clin Pharmacol Dept, London, England
[4] Univ Utrecht, Univ Med Ctr Utrecht, Dept Cardiol, Div Heart & Lungs, Utrecht, Netherlands
[5] UCL, Inst Cardiovasc Sci, Fac Populat Hlth Sci, London, England