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Rationale: Chronic obstructive pulmonary disease (COPD) is thought to result in rapid and progressive loss of lung function usually expressed as mean values for whole cohorts.
Objectives: Longitudinal studies evaluating individual lung function loss and other domains of COPD progression are needed.
Methods: We evaluated 1,198 stable, well-characterized patients with COPD (1,100 males) recruited in two centers (Florida and Tenerife, Spain) and annually monitored their multidomain progression from1997 to 2009. Patients werefollowed for a medianof 64 months and up to 10 years. Their individual FEV1 (L) and BODE index slopes, expressed as annual change, were evaluated using regression models for repeated measures. A total of 751 patients with at least three measurements were used for the analyses.
Measurements and Main Results: Eighteen percent of patients had a statistically significant FEV1 slope decline (286 ml/yr; 95% confidence interval [CI], 232 to 2278 ml/yr). Higher baseline FEV1 (relative risk, 1.857; 95% CI, 1.322-2.610; P , 0.001) and low body mass index (relative risk, 1.071; 95% CI, 1.035-1.106; P , 0.001) were independently associated with FEV1 decline. The BODE index had a statistically significant increase (0.55, 0.20-1.37 point/yr) in only 14% of patients and these had more severe baseline obstruction. Concordance between FEV1 and BODE change was low (k Cohen, 16%). Interestingly,73%of patients had no significant slope change in FEV1 or BODE. Only the BODE change was associated with mortality in patients without FEV1 progression.
Conclusions: The progression of COPD is very heterogeneous. Most patients show no statistically significant decline of FEV1 or increase in BODE. The multidimensional evaluation of COPD should offer insight into response to COPD management.
Keywords: chronic obstructive pulmonary disease; disease progression; FEV1; BODE index; longitudinal studies
Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality world-wide and is expected to increase over the coming decades. COPD is a complex heterogeneous disease and may have important individual variability in its progression (1).
Impaired growth of lung function during childhood and adolescence caused by infection, allergens, tobacco smoking, and genetic susceptibility increase the risk for COPD (1, 2). Nevertheless, an accelerated lung function decline usually estimated by the FEV1 is thought to be the classic feature of COPD, and the curves described by Fletcher and Peto (3) have...