@article {Vestbo00203-2018, author = {J{\o}rgen Vestbo and Mark Dransfield and Julie A. Anderson and Robert D. Brook and Peter M.A. Calverley and Bartolome R. Celli and Nicholas J. Cowans and Courtney Crim and Fernando Martinez and David E. Newby and Julie Yates and Peter Lange}, editor = {,}, title = {Impact of pre-enrolment medication use on clinical outcomes in SUMMIT}, volume = {5}, number = {1}, elocation-id = {00203-2018}, year = {2019}, doi = {10.1183/23120541.00203-2018}, publisher = {European Respiratory Society}, abstract = {In mortality trials including patients with COPD and heightened cardiovascular risk, patients{\textquoteright} treatments before entering the trial may affect the effects of inhaled medications during the study http://ow.ly/WRRb30nwyIEThe impact of prior treatment on results of clinical trials in chronic obstructive pulmonary disease (COPD) has been debated. We used data from the Study to Understand Mortality and Morbidity in COPD Trial to examine the impact of prior treatment on the effects of randomised study drugs on mortality and exacerbations.We used data on 16 417 patients with moderate COPD and heightened cardiovascular risk and information on prior medications to examine the effects of fluticasone furoate (FF), vilanterol (VI) and combined FF/VI compared to placebo on moderate and severe exacerbation as well as mortality. The study was event-driven with a median study exposure of 1.8 years. This study was registered with ClinicalTrials.gov, number NCT01313676.There were no consistent associations between treatment prior to study entry and the effects of FF, VI or FF/VI on exacerbations during the study. However, patients taking inhaled corticosteroids and one or more bronchodilators prior to study entry seemed to have a better effect of active treatments than of placebo on mortality (hazard ratio for FF/VI 0.65, 95\% CI 0.48{\textendash}0.89). Survival in those randomised to placebo was independent of treatment prior to study enrolment.Prior treatment appears to affect treatment effects on mortality but not exacerbations in a randomised controlled trial of patients with COPD and heightened cardiovascular risk.}, URL = {https://openres.ersjournals.com/content/5/1/00203-2018}, eprint = {https://openres.ersjournals.com/content/5/1/00203-2018.full.pdf}, journal = {ERJ Open Research} }