PURPOSE: Chronic obstructive pulmonary disease (COPD) is characterized by progressive decline in lung function but little is known about the rate of progression through severity stages over time. Our goal was to use Framingham Heart Study data to determine the proportion of COPD patients that progress to more severe stages of COPD.
METHODS: Framingham Heart Study participants who had spirometry data available were included in the analysis and categorized according to GOLD stages at the beginning and end of 12 years follow-up. Estimates of progression were stratified by smoking status, age and gender.
RESULTS: There were 583 individuals with airflow obstruction at the baseline visit;16.1% were never smokers, 42.5% always smokers and 37.6% intermittent smokers. In the cohort, 13.0% were <50 years, 60.9% were 50-69 years and 26.1% were 70+ years. The table shows the progression through the GOLD stages over 12 years. The mortality rate was progressively higher in each stage for each of the age groups. Of those in Stage 1 who had not died by 12 years, 66.2% were still Stage 1, 20.8% were Stage 2 and 13.0% were Stage 3/4. For those in Stage 2 who did not die, 61.4% were still in Stage 2 at 12 years and 18.6% were in Stage 3/4. When progression was stratified by smoking status, “always smokers” were most likely to progress. That is, they had the lowest proportion of patients in the same stage at baseline and 12 years.
CONCLUSION: These data provide information from a large, well-characterized cohort on the natural history and progression of COPD.
CLINICAL IMPLICATIONS: This data on disease progression provides information on the prognosis of patients with COPD based on their current stage of disease, age and smoking status and indicates those that continue to smoke have the worst prognosis.
DISCLOSURE: Todd Lee, Grant monies (from industry related sources) BOLD Project is sponsored by consortium of pharmaceutical manufacturers.