Rate of decline of lung function in COPD
Summary
The authors of this study evaluated post-bronchodilator changes in FEV1 over a three year period in 2,163 patients. They found that the mean rate of decline was 33±2 ml per year. There was significant variation. 38% of patients had a decline of greater than 40 ml per year, 31% had a decline of 21 to 40 ml per year, and 23% had a decline that ranged from 20 mg per year to an actual increase of 20 ml per year. 8% had an increase of more than 20 ml per year.
They found that the rate of decline therefore was highly variable, and increased rates of decline were demonstrated in current smokers, patients with bronchodilator reversibility, and patients diagnosed as having emphysema.
Reference
Vestbo J, et al. Changes in forced expiratory volume in 1 second over time in COPD. New England Journal of Medicine 2011 (September 29); 365:1184-1192.