title: Longitudinal studies are required.
authors.affiliation: Liverpool Vascular and Endovascular Service (LiVES), Royal Liverpool University Hospital, Liverpool L7 8XP, UK naseer.ahmad@liv.ac.uk.
authors.forename: Naseer
authors.initials: N
authors.lastname: Ahmad
authors.affiliation: Public Health, Epidemiology and Biostatistics, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: G Neil
authors.initials: GN
authors.lastname: Thomas
authors.affiliation: Department of Primary Care Research, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Paramjit
authors.initials: P
authors.lastname: Gill
authors.affiliation: Department of Vascular Surgery, Wirral University Hospital NHS Foundation Trust, Wirral CH49, UK.
authors.forename: Colin
authors.initials: C
authors.lastname: Chan
authors.affiliation: Liverpool Vascular and Endovascular Service (LiVES), Royal Liverpool University Hospital, Liverpool L7 8XP, UK.
authors.forename: Francesco
authors.initials: F
authors.lastname: Torella
mesh_terms: D000671:Amputation, Surgical; D006801:Humans; D008137:Longitudinal Studies