GOLD 2011 disease severity classification in COPDGene: a prospective cohort study

Area of Science:

• Pulmonary Medicine
• Clinical Research
• Respiratory Health

Background:

• The 2011 GOLD report uses symptoms, exacerbation history, and FEV1% to classify COPD severity and guide treatment.
• Current classification methods may influence patient categorization and subsequent risk assessment.

Purpose of the Study:

• To evaluate how different symptom instruments affect patient category assignment in COPD.
• To assess the influence of symptom measurement choice on prospective exacerbation risk within GOLD categories.

Main Methods:

• Recruited 4484 COPD patients (aged 45-80, smokers) from the COPDGene study.
• Categorized patients using mMRC dyspnea scale and SGRQ (as a CAT surrogate), alongside exacerbation history and FEV1% predicted.
• Employed k-sample permutation tests for statistical comparisons.

Main Results:

• Category assignments showed good agreement (κ=0.77) but were not identical between mMRC and SGRQ.
• Significant heterogeneity in exacerbation rates was observed within GOLD category D, particularly based on whether lung function or exacerbation history determined risk.
• Patients classified by both lung function and exacerbation history had the highest exacerbation rates (1.86/person-year).

Conclusions:

• Symptom assessment tool choice influences COPD patient classification.
• The GOLD classification highlights the importance of symptoms and exacerbation risk.
• Exacerbation risk stratification within the highest risk category (D) requires careful consideration of the defining parameters (lung function vs. exacerbation history).