[1] Univ Nottingham, Nottingham Clin Trials Unit, Bldg 42,Univ Pk, Nottingham NG7 2RD, England
[2] Univ Birmingham, Inst Appl Hlth Res, Coll Med & Dent Sci, Birmingham Clin Trials Unit BCTU, Publ Hlth Bldg, Birmingham B15 2TT, W Midlands, England
[3] Univ Aberdeen, Ctr Healthcare Randomised Trials CHaRT, Hlth Sci Bldg,Foresterhill, Aberdeen AB25 2ZD, Scotland
[4] Glasgow Caledonian Univ, NMAHP Res Unit, Cowcaddens Rd, Glasgow G4 0BA, Lanark, Scotland
[5] Univ Liverpool, Liverpool Clin Trials Ctr, Liverpool L69 3BX, Merseyside, England
[6] Liverpool Hlth Partners, Liverpool L69 3BX, Merseyside, England
[7] Univ Oxford, John Radcliffe Hosp, Kadoorie Ctr, Oxford Trauma,NDORMS, Level 3, Oxford OX3 9DU, England
[8] Univ Leicester, Coll Life Sci, Leicester Clin Trials Unit, Univ Rd, Leicester LE1 7RH, Leics, England