Correspondence

Pulmonary Rehabilitation

N Engl J Med 2009; 360:2678-2679June 18, 2009

Article

To the Editor:

In their Clinical Therapeutics article, Casaburi and ZuWallack (March 26 issue)1 do not discuss the BODE index and its role in evaluating the effect of pulmonary rehabilitation in chronic obstructive pulmonary disease (COPD). The BODE index incorporates the body-mass index (BMI), the severity of airflow obstruction and dyspnea, and exercise tolerance in a 10-point scale in which higher scores indicate a higher risk of death. This index has been shown to be a better predictor of mortality than Global Initiative for Chronic Obstructive Lung Disease (GOLD) staging, which classifies only the severity of obstruction.2 Changes in the BODE index correlate with favorable outcomes after surgery for lung-volume reduction3 and after pulmonary rehabilitation. In a controlled study, patients with COPD undergoing pulmonary rehabilitation had improved BODE scores and outcomes.4 The authors found that mortality due to respiratory disease at 2 years after pulmonary rehabilitation was 7%, as compared with 39% in the control group. Furthermore, their analysis showed that BODE scores returned to baseline after 2 years of follow-up, confirming what most of us already know about pulmonary rehabilitation: its benefits wane over time.

Luis M. Seijo, M.D.
Clínica Universitaria de Navarra, 31008 Pamplona, Spain
lmseijo@unav.es

4 References

1. 1

   Casaburi R, ZuWallack R. Pulmonary rehabilitation for management of chronic obstructive pulmonary disease. N Engl J Med 2009;360:1329-1335
   Full Text | Web of Science | Medline

2. 2

   Celli BR, Cote CG, Marin JM, et al. The body-mass index, airflow obstruction, dyspnea, and exercise capacity index in chronic obstructive pulmonary disease. N Engl J Med 2004;350:1005-1012
   Full Text | Web of Science | Medline

3. 3

   Martinez FJ, Han MK, Andrei AC, et al. Longitudinal change in the BODE index predicts mortality in severe emphysema. Am J Respir Crit Care Med 2008;178:491-499
   CrossRef | Web of Science | Medline

4. 4

   Cote CG, Celli BR. Pulmonary rehabilitation and the BODE index in COPD. Eur Respir J 2005;26:630-636
   CrossRef | Web of Science | Medline

Author/Editor Response

The BODE index was designed as an easily measured predictor of death in patients with COPD. It predicts mortality better than the forced expiratory volume in 1 second (FEV₁), but this is virtually a mathematical imperative, since the BODE index incorporates FEV₁ as one of its predicting variables. Studies have examined the BODE's usefulness in assessing outcome after therapeutic interventions. Cote and Celli found that patients with COPD undergoing pulmonary rehabilitation have improvements in their BODE score1 — as would be expected from well-described improvements in exercise tolerance and dyspnea.2 However, we cannot agree with Seijo's inference that the observed difference in mortality between patients who completed rehabilitation and patients who either declined to participate in or did not complete the intervention (the “control” group, although the study's authors did not designate it as such) demonstrates a survival benefit of pulmonary rehabilitation. Potential selection biases notwithstanding, patients who decline to participate in or do not complete rehabilitation have characteristics that are likely to lead to a poor prognosis3; Cote and Celli acknowledged this in their discussion. A randomized trial of pulmonary rehabilitation which is adequately powered for an outcome of survival remains a high priority.4

Richard Casaburi, Ph.D., M.D.
Los Angeles Biomedical Research Institute, Torrance, CA 90502
casaburi@ucla.edu

Richard ZuWallack, M.D.
St. Francis Hospital and Medical Center, Hartford, CT 06105

4 References

1. 1

   Cote CG, Celli BR. Pulmonary rehabilitation and the BODE index in COPD. Eur Respir J 2005;26:630-636
   CrossRef | Web of Science | Medline

2. 2

   Ries AL, Bauldoff GS, Carlin BW, et al. Pulmonary rehabilitation: joint ACCP/AACVPR evidence-based clinical practice guidelines. Chest 2007;131:Suppl:4S-42S
   CrossRef | Web of Science | Medline

3. 3

   Young P, Dewse M, Fergusson W, Kolbe J. Respiratory rehabilitation in chronic obstructive pulmonary disease: predictors of nonadherence. Eur Respir J 1999;13:855-859
   CrossRef | Web of Science | Medline

4. 4

   Troosters T, Casaburi R, Gosselink R, Decramer M. Pulmonary rehabilitation in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2005;172:19-38
   CrossRef | Web of Science | Medline