[1] Univ Cambridge, Dept Publ Hlth Primary Care, Cambridge CB1 8RN, England
[2] Univ Melbourne, Gen Practice & Primary Care Acad Ctr, Melbourne, Vic, Australia
[3] Univ Durham, Sch Med Pharm & Hlth, Stockton On Tees TS17 6BH, England
[4] Univ Oxford, Nuffield Dept Primary Care Hlth Sci, Oxford OX2 6GG, England
[5] Papworth Hosp NHS Fdn Trust, Dept Thorac Oncol, Cambridge CB23 3RE, England
[6] Univ Exeter, Exeter EX2 4TE, Devon, England
[7] Univ Western Australia, Dept Gen Practice, Perth, WA 6009, Australia