[1] Univ Birmingham, Ctr Patient Reported Outcomes Res, Birmingham, W Midlands, England
[2] Univ Birmingham, Inst Appl Hlth Res, Birmingham, W Midlands, England
[3] Queen Elizabeth Hosp Birmingham, Univ Hosp Birmingham NHS Fdn Trust, Birmingham, W Midlands, England
[4] Oxford Policy Management Ltd, Clarendon Ctr, Level 3, Oxford, England