Temporal transitions in COPD severity stages within the GOLD 2017 classification system.

Area of Science:

• Pulmonary Medicine
• Clinical Epidemiology

Background:

• The stability and individual transition frequencies within the GOLD 2017 COPD staging system remain largely unknown.
• Longitudinal data on COPD patient movement between stages is crucial for understanding disease dynamics.

Purpose of the Study:

• To evaluate the stability of the GOLD 2017 COPD staging system over five years.
• To determine the frequency of individual transitions between COPD stages.

Main Methods:

• Re-analysis of the CHAIN cohort (959 COPD participants) using GOLD 2017 criteria.
• Aggregation of individual patient stage changes into Markov chains.
• Evaluation of group stability using joinpoint regression over five years of follow-up.

Main Results:

• Group proportions in GOLD 2017 stages (A, B, C, D) remained stable from year one to five.
• Significant individual patient transitions between stages were observed, particularly in stages C and D.
• Annual probabilities of remaining in stage C ranged from 16-31%, and in stage D from 23-43%.

Conclusions:

• The GOLD 2017 COPD staging demonstrates apparent group stability.
• Substantial year-to-year variability exists at the individual patient level, indicating dynamic changes in COPD severity.