Validity of the GOLD 2017 classification in the prediction of mortality and respiratory hospitalization in patients with chronic obstructive pulmonary disease

Abstract

Background: The Global Initiative for Chronic Obstructive Lung Disease (GOLD) released an updated document in 2017 that excluded the spirometric parameter in the classification of patients. The validity of this new classification system in predicting mortality and respiratory hospitalization is still uncertain.

Methods: Outpatients (n=149) with chronic obstructive pulmonary disease (COPD) who underwent spirometry and six-minutes walking test from October 2011 to September 2013 were enrolled. The overall mortality and rate of respiratory hospitalization over a median of 61 months were analyzed. Kaplan-Meier survival analyses, receiver operaing curve analyses with areas under the curve (AUCs), and logistic regression analyses for GOLD 2007, GOLD 2011, GOLD 2017, and/or BODE index were performed to evaluate their abilities to predict mortality and respiratory hospitalization.

Results: Forty-two (53.2%) patients in 2011 GOLD C or D group were categorized into 2017 GOLD A or B group. The odds ratios of GOLD 2017 group C and group D relative to group A were 7.55 (95% CI, 1.25–45.8) and 25.0 (95% CI, 6.01–102.9) for respiratory hospitalization. Patients in GOLD 2017 group A and group B had significantly better survival (log-rank test, p<0.001) compared with patients in group D; however, survival among patients in GOLD 2007 groups and GOLD 2011 groups was comparable. The AUC values for GOLD 2007, GOLD 2011, GOLD 2017, and BODE index were 0.573, 0.624, 0.691, 0.692 for mortality (p=0.013) and 0.697, 0.707, 0.741, and 0.754 for respiratory hospitalization (p=0.296), respectively.

Conclusion: The new GOLD classification may perform better than the previous classifications in terms of predicting mortality and respiratory hospitalization.

Keywords:

• COPD
• GOLD classification
• mortality
• respiratory hospitalization

Acknowledgments

The authors thank all residents of Gyeongsang National University Hospital who participated in collecting data in this study.

Abbreviation list

GOLD, Global Initiative for Chronic Obstructive Lung Disease; COPD, Chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in one second; mMRC, modified Medical Research Council; CAT, COPD Assessment Test; BODE, the BMI, obstruction, dyspnea, exercise; FVC, forced vital capacity; 6MWT, six-minute walk test; DLco, diffusing capacity of carbon monoxide; RV, residual volume; ORs, Odds ratios; CIs, confidence intervals; ROC, Receiver Operation Characteristic;AUCs, areas under the curves.

Author contributions

All authors contributed to data analysis, drafting or revising the article, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

All authors certify that there is no conflicts of interest with any financial organization regarding the material discussed in the manuscript.