title: Evaluation of COPD progression based on spirometry and exercise capacity.
abstract: BACKGROUND
  Chronic obstructive pulmonary disease (COPD) is characterized by an airflow limitation that is usually progressive. The progression of COPD expressed as the rate of an annual decline in FEV 1 is very heterogeneous. Exercise capacity in COPD patients is often diminished and becomes worsened over the time. The purpose of the study was to examine how the change in FEV 1 and exercise capacity would deteriorate over long-term observation.
  
  
  METHODS
  A total of 22 men with COPD were examined. At the beginning the average age was 59 ± 8.1 years and the mean post-bronchodilator FEV 1 was 52 ± 14.9% predicted. Pulmonary function testing was performed at entry and then each year for 10 years, and exercise testing on a cycle ergometer was performed at entry and after 10 years.
  
  
  RESULTS
  FEV 1 and maximum oxygen uptake (VO2max), maximum mechanical work (W max ), maximum minute ventilation (V Emax ) and maximum tidal volume (V Tmax ) declined significantly over the observation time. The mean annual decline in FEV 1 was 42 ± 37 mL, and the mean decline for VO 2max was 30 ± 15 mL/min/yr and 0.44 ± 0.25 mL/min/kg/yr. Regression analysis revealed that the changes in FEV 1 do not predict changes in VO2max. We observed a correlation between the annual change in V Emax and annual change in VO2max (r = 0.51 p < 0.05). The baseline FEV 1 (expressed as a percentage of predicted and in absolute values) is the predictor of FEV 1 annual decline (r = 0.74 and 0.82; p < 0.05).
  
  
  CONCLUSIONS
  We observed over time deterioration in exercise capacity in COPD patients which is independent of decline in airflow limitation. The long term follow-up of exercise capacity is important in monitoring of COPD patients in addition to pulmonary function.
authors.affiliation: Department and Clinic of P ulmonology, Medical University of Silesia in Katowice. trzaska@mp.pl
authors.forename: Marzena
authors.initials: M
authors.lastname: Trzaska-Sobczak
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Brożek
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Farnik
authors.forename: Władysław
authors.initials: W
authors.lastname: Pierzchała
mesh_terms: D000368:Aged; D018450:Disease Progression; D005080:Exercise Test; D017079:Exercise Tolerance; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D012044:Regression Analysis; D012129:Respiratory Function Tests; D013147:Spirometry