Is COPD a Progressive Disease? A Long Term Bode Cohort Observation

BACKGROUND:

The Global Initiative for Obstructive Lung Diseases (GOLD) defines COPD as a disease that is usually progressive. GOLD also provides a spirometric classification of airflow limitation. However, little is known about the long-term changes of patients in different GOLD grades.

OBJECTIVE:
Explore the proportion and characteristics of COPD patients that change their spirometric GOLD grade over long-term follow-up.

METHODS:
Patients alive for at least 8 years since recruitment and those who died with at least 4 years of repeated spirometric measurements were selected from the BODE cohort database.

We purposely included the group of non survivors to avoid a "survival selection" bias. The proportion of patients that had a change (improvement or worsening) in their spirometric GOLD grading was calculated and their characteristics compared with those that remained in the same grade.

RESULTS:
A total of 318 patients were included in the survivor and 217 in the non-survivor groups. Nine percent of survivors and 11% of non survivors had an improvement of at least one GOLD grade. Seventy one percent of survivors and non-survivors remained in the same GOLD grade. Those that improved had a greater degree of airway obstruction at baseline.

CONCLUSIONS:
In this selected population of COPD patients, a high proportion of patients remained in the same spirometric GOLD grade or improved in a long-term follow-up. These findings suggest that once diagnosed, COPD is usually a non-progressive disease.

CITA DEL ARTÍCULO  PLoS One. 2016 Apr 21;11(4):e0151856. doi: 10.1371/journal.pone.0151856. eCollection 2016.