[1] Univ Newcastle, Ctr Hlth Serv Res, Sch Populat & Hlth Sci, Newcastle Upon Tyne NE3 4AA, Tyne & Wear, England
[2] Univ Durham, Sch Hlth, Wolfson Res Unit, Stockton On Tees, England
[3] Univ Leeds, Sch Healthcare, Leeds, W Yorkshire, England
[4] Univ Leicester, Dept Cardiovasc Sci, Leicester Royal Infirm, Leicester, Leics, England
[5] Univ Newcastle, Clin Res Facil, Royal Victoria Infirm, Newcastle Upon Tyne, Tyne & Wear, England