{Reference Type}: Letter {Title}: Challenges of Using Routinely Collected Healthcare System Data in Randomised Trials. {Author}: Twine CP;Ahmed H;Lugg-Widger FV;Waldron CA;Bown MJ;Sydes MR; {Journal}: Eur J Vasc Endovasc Surg {Volume}: 0 {Issue}: 0 {Year}: 2024 May 10 {Factor}: 6.427 {DOI}: 10.1016/j.ejvs.2024.05.010