title: Comparing the 2007 and 2011 GOLD Classifications as Predictors of all-Cause Mortality and Morbidity in COPD.
abstract: To better classify patients with chronic obstructive pulmonary disease (COPD) for prognostic purposes and to tailor treatment, the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2007 classification was revised in 2011. The primary aim of the current data analyses was to evaluate the accuracy of the GOLD 2007 and 2011 GOLD classifications to predict all-cause mortality and morbidity in a well-described COPD cohort. The prognostic values of both GOLD classifications, expressed as the C-statistic, were assessed in the Cohort of Mortality and Inflammation in COPD (COMIC) study of 795 COPD patients, with a follow-up of 3 years. Outcomes were all-cause mortality and morbidity. Morbidity was defined as time until first COPD-related hospitalisation and time until first community-acquired pneumonia (CAP). The prognostic value of the GOLD 2011 classification was compared between symptom classification based on the modified Medical Research Council (mMRC) score and the Clinical COPD Questionnaire (CCQ) scores with two different thresholds. Although the GOLD 2011 CCQ classification had the highest accuracy to predict mortality and morbidity in our study, the C-statistics differed only numerically. Furthermore, our study showed that the instrument used to determine the level of symptoms in the GOLD 2011 classification has not only important consequences on the mortality prognosis, but also affects the morbidity prognosis in COPD. Therefore, patients' estimated prognosis could alter when different types of tools are used to evaluate the prognosis.
authors.affiliation: a Medical School Twente, Medisch Spectrum Twente , Enschede , The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Brusse-Keizer
authors.affiliation: b Department of Pulmonary Medicine , Medisch Spectrum Twente , Enschede , The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Klatte
authors.affiliation: b Department of Pulmonary Medicine , Medisch Spectrum Twente , Enschede , The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Zuur-Telgen
authors.affiliation: b Department of Pulmonary Medicine , Medisch Spectrum Twente , Enschede , The Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Koehorst-Ter Huurne
authors.affiliation: a Medical School Twente, Medisch Spectrum Twente , Enschede , The Netherlands.|c Department of Research Methodology , Measurement, and Data Analysis, University of Twente , Enschede , The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: van der Palen
authors.affiliation: b Department of Pulmonary Medicine , Medisch Spectrum Twente , Enschede , The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: VanderValk
mesh_terms: D000368:Aged; D002423:Cause of Death; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000209:etiology; D018450:Disease Progression; D005260:Female; D006760:Hospitalization; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000209:etiology*; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000145:classification* / Q000150:complications* / Q000401:mortality; D018570:Risk Assessment / Q000379:methods; D012720:Severity of Illness Index; D015996:Survival Rate; D013997:Time Factors
keywords: Acute exacerbation COPD; C-statistic; pneumonia; prognosis survival