Chest
Volume 128, Issue 1, July 2005, Pages 62-69
Journal home page for Chest

Clinical Investigations
Copd
Exercise Capacity Deterioration in Patients With COPD: Longitudinal Evaluation Over 5 Years

https://doi.org/10.1378/chest.128.1.62Get rights and content

Background

Although exercise capacity is an important outcome measure in patients with COPD, its longitudinal course has not been analyzed in comparison to the change in pulmonary function.

Purpose

To examine how exercise capacity would deteriorate over time in patients with COPD, and what factors would contribute to it.

Methods

A total of 137 male outpatients with moderate-to-very-severe COPD were examined. The average age was 69.0 ± 6.6 years (± SD), and the mean postbronchodilator FEV1 was 45.9 ± 15.4% predicted. Progressive cycle ergometry and pulmonary function testing were performed at entry, and every 6 months thereafter over 5 years. Due to the presence of missing data, a mixed-effect model analysis was then used to estimate the longitudinal changes in various clinical parameters.

Results

Peak oxygen uptake ( V˙o2), peak minute ventilation ( V˙e), and peak tidal volume (Vt) during exercise declined significantly over time (p < 0.0001), which was no less rapid than the deterioration in FEV1. The mean decline rates for peak V˙o2 were 32 ± 60 mL/min/yr and 0.5 ± 1.0 mL/min/kg/yr. Multiple regression analysis revealed that the changes in peak V˙e, peak Vt, and peak respiratory rates were significant predictors for the change in peak V˙o2.

Conclusion

We demonstrated clear evidence of measurable and progressive deterioration in exercise capacity in COPD patients, which was no less rapid than the decline in airflow limitation. Dynamic ventilatory constraints during exercise also deteriorated over time, which most significantly contributed to this exercise capacity deterioration. In addition to pulmonary function, the longitudinal follow-up of exercise capacity is important not to miss the overall deterioration in COPD.

Section snippets

Subjects

We recruited 137 consecutive male outpatients with moderate-to-very-severe COPD, as defined by the American Thoracic Society and European Respiratory Society 2004 guidelines.1 These participants consisted of 131 patients enrolled in a previous study6 investigating the relationship between the baseline measures and 5-year mortality between September 1995 and January 1997, and 6 patients who were added from February 1997 to April 1997. The entry criteria included the following: (1) a smoking

Results

The baseline characteristics of the 137 male patients are shown in Table 1. Their average age was 69.0 ± 6.6 years, and postbronchodilator FEV1 was 45.9 ± 15.4% predicted. When the patients were classified according to their COPD severity based on postbronchodilator FEV1, 53 patients (39%) had moderate COPD (FEV1 ≥ 50 to < 80% predicted), 59 patients (43%) had severe COPD (FEV1 ≥ 30 to < 50% predicted), and 25 patients (18%) had very severe COPD (FEV1 < 30% predicted).

Changes in peak V˙o2,

Discussion

We found clear evidence of a measurable and progressive deterioration in exercise capacity in patients with moderate-to-very-severe COPD. To our knowledge, this is the first published study on COPD to demonstrate a longitudinal decline in laboratory exercise capacity evaluated by peak V˙o2 on progressive cycle ergometry prospectively over 5 years. We previously reported that peak V˙o2 was the most significant predictor of mortality among several indexes evaluating COPD,6 and we could

References (36)

  • NJ Gross

    Extrapulmonary effects of chronic obstructive pulmonary disease

    Curr Opin Pulm Med

    (2001)
  • PW Jones

    Health status measurement in chronic obstructive pulmonary disease

    Thorax

    (2001)
  • T Oga et al.

    Analysis of the factors related to mortality in chronic obstructive pulmonary disease: role of exercise capacity and health status

    Am J Respir Crit Care Med

    (2003)
  • BR Celli et al.

    The body-mass index, airflow obstruction, dyspnea, and exercise capacity index in chronic obstructive pulmonary disease

    N Engl J Med

    (2004)
  • VM Pinto-Plata et al.

    The 6-min walk distance: change over time and value as a predictor of survival in severe COPD

    Eur Respir J

    (2004)
  • D Strachan et al.

    Statistical methods

    Eur Respir J

    (1998)
  • Medical Section of the American Lung Association

    Standardization of spirometry, 1994 update

    Am J Respir Crit Care Med

    (1994)
  • Japan Society of Chest Diseases

    The predicted values of pulmonary function testing in Japanese [in Japanese]

    Jpn J Thoracic Dis

    (1993)
  • Cited by (98)

    • Effect of exercise capacity on perception of dyspnea, psychological symptoms and quality of life in patients with chronic obstructive pulmonary disease

      2020, Heart and Lung
      Citation Excerpt :

      Exercise capacity is a very important parameter being used recently to determine the prognosis and response to therapeutic interventions.22 Just like FEV1, walking distance also decreases in time in COPD patients.21–24 However, this decrease in walking distance is independent from respiratory functions.21

    View all citing articles on Scopus
    View full text