1 Department of Respiratory Sciences, University of Leicester, Leicester LE1 7RH, UK; Department of Infectious Diseases and HIV Medicine, University Hospitals of Leicester NHS Trust, Leicester, UK.
2 Department of Health Sciences, University of Leicester, Leicester LE1 7RH, UK.
3 Department of Cardiovascular Diseases, University of Leicester, Leicester LE1 7RH, UK.
4 Clinical Library Services, University Hospitals of Leicester NHS Trust, Leicester, UK.
5 Department of Statistics, University of Warwick, Coventry, UK; Centre for Health Economics, University of York, York, UK.
6 Division of Epidemiology and Public Health, University of Nottingham, Nottingham, UK.
7 Department of Respiratory Sciences, University of Leicester, Leicester LE1 7RH, UK; Department of Infectious Diseases and HIV Medicine, University Hospitals of Leicester NHS Trust, Leicester, UK. Electronic address: manish.pareek@leicester.ac.uk.