1 MRC/CSO Social and Public Health Sciences Unit, Institute of Health & WellBeing, University of Glasgow, Glasgow G3 7HR, UK; Robertson Centre for Biostatistics, Institute of Health & WellBeing, University of Glasgow, Glasgow G3 7HR, UK. Electronic address: rod.taylor@glasgow.ac.uk.
2 Knowledge Centre for Rehabilitation and Palliative Care, Nyborg, Denmark; University of Southern Denmark, Odense, Denmark; Odense University Hospital, Odense, Denmark.
3 Department of Cardiac Surgery, Physiotherapy Unit, Ibrahim Cardiac Hospital & Research Institute, Dhaka, Bangladesh.