Prognostic Properties of the GOLD 2023 Classification System

Abstract

Introduction

Recently, the Global Initiative for Chronic Obstructive Lung Disease (GOLD) has published an update on the Global Strategy for Prevention, Diagnosis and Management of COPD, introducing a new classification of chronic obstructive pulmonary disease (COPD). Our aim was to assess the prognostic value of the new GOLD classification system in comparison with the previous GOLD classification systems (GOLD stages I–IV and GOLD groups A-D) and the BODE index.

Methods

We used the data of 784 patients with COPD from the Czech Multicenter Research Database of COPD. Patient survival was analyzed with the use of Kaplan–Meier estimate and Cox model of proportional risks. ROC analysis and area under curve (AUC) were used for comparison of GOLD classifications and BODE index. The analyses were performed with the use of software R (version 4.2.0).

Results

We analyzed data of 782 patients with complete data on GOLD classifications. The study population comprised 72.9% of men, 89.1% current or former smokers, with a mean age of 66.6 years, a mean BMI of 27.4 and a mean FEV₁ 44.9% of predicted. Probability of 5-year survival differed by GOLD classification. Application of the 2023 GOLD classification showed increased risk of death in group B (HR 1.82, 95% CI 1.14–2.92; p = 0.013) and in group E (HR 2.48, 95% CI 1.54–3.99; p˂0.001). The ROC analysis showed that the overall prognostic value of the 2023 GOLD classification was similarly weak to previous A-D GOLD classification schemes (AUCs 0.557–0.576) and was lower compared to the GOLD 1–4 system (AUC 0.614) and even lower when compared to the BODE index (AUC 0.715).

Conclusion

We concluded that the new GOLD classification system has poor prognostic properties and that specific prediction tools (eg, the BODE index) should be used for mortality risk assessment.

Keywords:

• GOLD classification
• COPD
• mortality
• prognosis

Abbreviations

AUC, area under the curve; BMI, body mass index; BODE, acronym for Body mass index, Obstruction, Dyspnea and Exercise tolerance; CADOT, Chronic heart failure, Age, Dyspnea, Obstruction and Diffusing capacity of the lungs for carbon monoxide; CI, confidence interval; CKD, chronic kidney disease; CMRD, Czech Multicenter Research Database of COPD; COPD, chronic obstructive pulmonary disease; HR, hazard ratio; CHF, chronic heart failure; GOLD, Global Initiative for Chronic Obstructive Lung Disease; IQR, interquartile range; NYHA, New York Heart Association; PC, physical capacity; SD, standard deviation; TNM, TNM Classification of Malignant Tumors.

Study Registration

The CMRD project has been registered at ClinicalTrials.gov with the identifier NCT01923051. Website: https://chopn.registry.cz/index-en.php.

Data Sharing Statement

The datasets analyzed during the study are available from the corresponding author on a reasonable request.

Ethics

The CMRD project was conducted in accordance with the Declaration of Helsinki and the Czech and European Union legislation. The CMRD study was approved by the Multicenter Ethics Committee of Masaryk University, Brno, Czech Republic (date of approval: Jan 16th, 2013, protocol code: CHOPN) and by regional review boards of all fourteen participating centers.⁶ All patients signed a written informed consent at study enrolment and agreed to use their anonymized data for scientific purpose.

Acknowledgments

The authors thank to all physicians for their help with data collection and input, as well as to all patients that participated in the CMRD study and agreed to share their data with the scientific community.

Author Contributions

Vladimir Koblizek is the senior author. All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

Dr Jaromir Zatloukal reports personal fees from AstraZeneca, personal fees from Boehringer-Ingelheim, personal fees from Chiesi, outside the submitted work. Dr Vladimir Koblizek reports grants, personal fees from Boehringer Ingelheim CZ, grants from Boehringer Ingelheim RCV, personal fees from AstraZeneca CZ, grants, personal fees from Angelini CZ, personal fees from Chiesi CZ, personal fees from Berlin Chemie CZ, during the conduct of the study; personal fees from MSD CZ, personal fees from Gilead CZ, outside the submitted work. The authors of this article report no other conflicts of interest with relevance to this study.

Additional information

Funding

Supported by the Czech Pneumological and Phthisiological Society (open access publication fee grant). The CMRD research project was funded by the Ministry of Health of the Czech Republic (MH CZ‐DRO FNBr 65269705), and a consortium of pharmaceutical companies (Sandoz, Novartis, GSK, CSL Behring, Cipla, Boehringer Ingelheim, AstraZeneca, and Angelini). The companies supported the CMRD project via unrestricted research grants. The supporters had no role in the study design, data analysis or in preparation of the manuscript. All opinions, results, and conclusions reported in this paper are independent from the sponsors.