A score to predict short-term risk of COPD exacerbations (SCOPEX)

Abstract

Barry J Make,1 Göran Eriksson,2 Peter M Calverley,3 Christine R Jenkins,4 Dirkje S Postma,5 Stefan Peterson,6 Ollie Östlund,7 Antonio Anzueto8 1Division of Pulmonary Sciences and Critical Care Medicine, National Jewish Health, University of Colorado Denver School of Medicine, Denver, CO, USA; 2Department of Respiratory Medicine and Allergology, University Hospital, Lund, Sweden; 3Pulmonary and Rehabilitation Research Group, University Hospital Aintree, Liverpool, UK; 4George Institute for Global Health, The University of Sydney and Concord Clinical School, Woolcock Institute of Medical Research, Sydney, NSW, Australia; 5Department of Pulmonology, University of Groningen and GRIAC Research Institute, University Medical Center Groningen, Groningen, The Netherlands; 6StatMind AB, Lund, Sweden; 7Department of Medical Sciences and Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden; 8Department of Pulmonary/Critical Care, University of Texas Health Sciences Center and South Texas Veterans Healthcare System, San Antonio, TX, USA Background: There is no clinically useful score to predict chronic obstructive pulmonary disease (COPD) exacerbations. We aimed to derive this by analyzing data from three existing COPD clinical trials of budesonide/formoterol, formoterol, or placebo in patients with moderate-to-very-severe COPD and a history of exacerbations in the previous year. Methods: Predictive variables were selected using Cox regression for time to first severe COPD exacerbation. We determined absolute risk estimates for an exacerbation by identifying variables in a binomial model, adjusting for observation time, study, and treatment. The model was further reduced to clinically useful variables and the final regression coefficients scaled to obtain risk scores of 0–100 to predict an exacerbation within 6 months. Receiver operating characteristic (ROC) curves and the corresponding C-index were used to investigate the discriminatory properties of predictive variables. Results: The best predictors of an exacerbation in the next 6 months were more COPD maintenance medications prior to the trial, higher mean daily reliever use, more exacerbations during the previous year, lower forced expiratory volume in 1 second/forced vital capacity ratio, and female sex. Using these risk variables, we developed a score to predict short-term (6-month) risk of COPD exacerbations (SCOPEX). Budesonide/formoterol reduced future exacerbation risk more than formoterol or as-needed short-acting ß2-agonist (salbutamol). Conclusion: SCOPEX incorporates easily identifiable patient characteristics and can be readily applied in clinical practice to target therapy to reduce COPD exacerbations in patients at the highest risk. Keywords: chronic obstructive pulmonary disease, exacerbation, model, predictor, inhaled corticosteroids, bronchodilators