Predicting Outcomes in Chronic Obstructive Pulmonary Disease
http://www.100md.com
《新英格兰医药杂志》
To the Editor: Celli and colleagues (March 4 issue)1 propose the use of a new index (the BODE index) that has excellent predictive power with regard to outcome in chronic obstructive pulmonary disease (COPD). The BODE index combines four variables: the body-mass index (B); the degree of airflow obstruction (O), assessed according to the forced expiratory volume in one second (FEV1); the degree of dyspnea (D) on the modified Medical Research Council dyspnea scale; and exercise capacity (E), assessed as the distance walked in six minutes. We have found that the presence of the paradoxical inspiratory movement of the lateral rib margin (Hoover's sign) in patients with COPD was associated with increased dyspnea (during usual activities and after exercise) and increased use of health resources.2 This finding was independent of the FEV1 and the body-mass index. We suggest that this simple finding on the physical examination may also be considered a possible factor in the design of an index of the outcome of COPD.
Eduardo Garcia-Pachon, M.D.
Isabel Padilla-Nava, M.D.
Hospital General Universitario
E-03203 Elche, Spain
egpachon@hotmail.com
References
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.
Garcia-Pachon E, Padilla-Navas I. Clinical implications of Hoover's sign in chronic obstructive pulmonary disease. Eur J Intern Med 2004;15:50-53.
To the Editor: Celli and colleagues propose a multidimensional grading system for predicting the risk of death in patients with COPD, but conspicuously absent from their index is consideration of the frequency of exacerbations.1
Stefan S. Kostianev, M.D., Ph.D.
Dimitar H. Iluchev, M.D., Ph.D.
Medical University
4002 Plovdiv, Bulgaria
kostian@plovdiv.techno-link.com
References
Management of exacerbations of COPD. Thorax 2004;59:Suppl 1:131-156.
To the Editor: Several considerations limit the validity and generalizability of the BODE index. Because the authors studied prevalent cases of COPD rather than COPD in an inception cohort1 and did not adjust for the duration of symptoms, their findings support the tautology that patients who have more advanced disease than others have a worse prognosis; however, their findings do little to facilitate differentiation among patients at any given point in the course of disease. Because they excluded patients with heart failure, unstable angina, and other illnesses likely to result in death within three years, their sample is not representative of the larger population with COPD, as evidenced by the atypically high percentage of patients who died of respiratory failure.2,3 Finally, the authors did not evaluate several potentially important predictors of survival in the model, including smoking status, hypoxemia, use of medications, and frequency of exacerbations — omissions suggesting that there is room for additional improvement.
Viji Sankaranarayanan, M.D.
Tomasz Ziedalski, M.D.
Stanford University
Stanford, CA 94305
vijisank@stanford.edu
Michael K. Gould, M.D.
Palo Alto Veterans Affairs Health Care System
Palo Alto, CA 94304
References
Sackett DL, Haynes B, Guyatt G, Tugwell P. Clinical epidemiology: a basic science for clinical medicine. Boston: Little, Brown, 1991:177.
Kjoller E, Kober L, Iversen K, Torp-Pedersen C. Importance of chronic obstructive pulmonary disease for prognosis and diagnosis of congestive heart failure in patients with acute myocardial infarction. Eur J Heart Fail 2004;6:71-77.
Pauwels RA, Buist AS, Calverley PM, Jenkins CR, Hurd SS. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: NHLBI/WHO Global Initiative for Chronic Obstructive Lung Disease (GOLD) Workshop summary. Am J Respir Crit Care Med 2001;163:1256-1276.
To the Editor: The multidimensional BODE index described by Celli et al. could be of use in choosing the optimal moment for lung transplantation in patients with COPD. We retrospectively analyzed the BODE index score in 52 patients (mean [±SD] age, 52±8 years) who had undergone transplantation for COPD in our center. The majority of patients had BODE scores of 7 or higher (Figure 1), and the five-year survival rate was 48 percent (according to Kaplan–Meier analysis), similar to that described in an international registry.1 These results suggest it may be possible to recommend the use of the BODE index to improve the selection of patients with COPD for lung transplantation since, according to the data presented by Celli et al., BODE scores of 7 or higher are associated with 20 percent survival at 52 months without transplantation, whereas according to our results the 5-year survival is 48 percent after transplantation.
Figure 1. BODE Index Scores in Lung-Transplant Recipients.
Piedad Ussetti, M.D.
Rosalia Laporta, M.D.
Clínica Puerta de Hierro
28035 Madrid, Spain
pied2152@separ.es
References
Hertz MI, Mohacsi PJ, Taylor DO, et al. The registry of the International Society for Heart and Lung Transplantation: introduction to the Twentieth Annual Reports -- 2003. J Heart Lung Transplant 2003;22:610-615.
Dr. Celli replies: Garcia-Pachon and Padilla-Nava describe the value of Hoover's sign (retraction of the intercostal muscles of the lower rib cage) to predict dyspnea and use of resources. Indeed, Hoover's sign is seen in patients with severe disease but may be a less sensitive test in patients with less airflow obstruction, who do not need to recruit accessory muscles to ventilate.1
Drs. Kostianev and Iluchev as well as Dr. Sankaranarayanan and colleagues point out the lack of blood-gas exchange and acute exacerbations as possible variables to be included in any index. The partial pressures of arterial oxygen and carbon dioxide were measured in the first 207 patients in our study and found to be independent predictors of the risk of death. However, they failed to improve the model in the multivariable analysis. My coauthors and I omitted this information from the final version of the manuscript to keep it within space limitations. We have found the BODE index to be an excellent predictor of the use of health resources and of exacerbations.2,3 We considered exacerbation of COPD an outcome rather than a defining variable, in the same way that myocardial infarction is an outcome of coronary artery disease and not one of its determinants. However, it is very likely that the presence of recurrent exacerbations could be a marker of poor outcome.4
Dr. Sankaranarayanan and colleagues correctly indicate that the BODE index was not evaluated in an inception cohort and therefore cannot be generalized to all patients with COPD. We agree with that epidemiologic statement but would like to point out that the index was developed for clinicians who, when examining patients, need simple tools that can help them better pinpoint the severity of the disease.
We are extremely pleased with the potential use of the BODE index in the timing of lung transplantation, as suggested by Drs. Ussetti and Laporta. Indeed, at similar FEV1 values, patients with higher BODE scores carry a worse prognosis than those with lower scores and may very well need to undergo transplantation earlier. Along with the use of the BODE index in many other possible therapeutic interventions and their comparisons, this would be an exciting use of this tool.
Bartolome R. Celli, M.D.
Caritas St. Elizabeth's Medical Center
Boston, MA 02135
References
Roussos C, Macklem PT. The respiratory muscles. N Engl J Med 1982;307:786-797.
Marin JM, Alonso J, Sanchez A, et al. Value of current COPD classification versus a multiple component staging system (SCORE) as predictor of health care resource utilization. Am J Respir Crit Care Med 2002;165:A43.abstract.
Cote CG, Marin JM, Celli BR. Factors that predict health care resources utilization (HCUR) in COPD. Am J Respir Crit Care Med 1999;159:Suppl:A912-A912. abstract.
Seemungal TAR, Donaldson GC, Paul EA, Bestall JC, Jeffries DJ, Wedzicha JA. Effect of exacerbation on quality of life in patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med 1998;157:1418-1422.
Eduardo Garcia-Pachon, M.D.
Isabel Padilla-Nava, M.D.
Hospital General Universitario
E-03203 Elche, Spain
egpachon@hotmail.com
References
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.
Garcia-Pachon E, Padilla-Navas I. Clinical implications of Hoover's sign in chronic obstructive pulmonary disease. Eur J Intern Med 2004;15:50-53.
To the Editor: Celli and colleagues propose a multidimensional grading system for predicting the risk of death in patients with COPD, but conspicuously absent from their index is consideration of the frequency of exacerbations.1
Stefan S. Kostianev, M.D., Ph.D.
Dimitar H. Iluchev, M.D., Ph.D.
Medical University
4002 Plovdiv, Bulgaria
kostian@plovdiv.techno-link.com
References
Management of exacerbations of COPD. Thorax 2004;59:Suppl 1:131-156.
To the Editor: Several considerations limit the validity and generalizability of the BODE index. Because the authors studied prevalent cases of COPD rather than COPD in an inception cohort1 and did not adjust for the duration of symptoms, their findings support the tautology that patients who have more advanced disease than others have a worse prognosis; however, their findings do little to facilitate differentiation among patients at any given point in the course of disease. Because they excluded patients with heart failure, unstable angina, and other illnesses likely to result in death within three years, their sample is not representative of the larger population with COPD, as evidenced by the atypically high percentage of patients who died of respiratory failure.2,3 Finally, the authors did not evaluate several potentially important predictors of survival in the model, including smoking status, hypoxemia, use of medications, and frequency of exacerbations — omissions suggesting that there is room for additional improvement.
Viji Sankaranarayanan, M.D.
Tomasz Ziedalski, M.D.
Stanford University
Stanford, CA 94305
vijisank@stanford.edu
Michael K. Gould, M.D.
Palo Alto Veterans Affairs Health Care System
Palo Alto, CA 94304
References
Sackett DL, Haynes B, Guyatt G, Tugwell P. Clinical epidemiology: a basic science for clinical medicine. Boston: Little, Brown, 1991:177.
Kjoller E, Kober L, Iversen K, Torp-Pedersen C. Importance of chronic obstructive pulmonary disease for prognosis and diagnosis of congestive heart failure in patients with acute myocardial infarction. Eur J Heart Fail 2004;6:71-77.
Pauwels RA, Buist AS, Calverley PM, Jenkins CR, Hurd SS. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: NHLBI/WHO Global Initiative for Chronic Obstructive Lung Disease (GOLD) Workshop summary. Am J Respir Crit Care Med 2001;163:1256-1276.
To the Editor: The multidimensional BODE index described by Celli et al. could be of use in choosing the optimal moment for lung transplantation in patients with COPD. We retrospectively analyzed the BODE index score in 52 patients (mean [±SD] age, 52±8 years) who had undergone transplantation for COPD in our center. The majority of patients had BODE scores of 7 or higher (Figure 1), and the five-year survival rate was 48 percent (according to Kaplan–Meier analysis), similar to that described in an international registry.1 These results suggest it may be possible to recommend the use of the BODE index to improve the selection of patients with COPD for lung transplantation since, according to the data presented by Celli et al., BODE scores of 7 or higher are associated with 20 percent survival at 52 months without transplantation, whereas according to our results the 5-year survival is 48 percent after transplantation.
Figure 1. BODE Index Scores in Lung-Transplant Recipients.
Piedad Ussetti, M.D.
Rosalia Laporta, M.D.
Clínica Puerta de Hierro
28035 Madrid, Spain
pied2152@separ.es
References
Hertz MI, Mohacsi PJ, Taylor DO, et al. The registry of the International Society for Heart and Lung Transplantation: introduction to the Twentieth Annual Reports -- 2003. J Heart Lung Transplant 2003;22:610-615.
Dr. Celli replies: Garcia-Pachon and Padilla-Nava describe the value of Hoover's sign (retraction of the intercostal muscles of the lower rib cage) to predict dyspnea and use of resources. Indeed, Hoover's sign is seen in patients with severe disease but may be a less sensitive test in patients with less airflow obstruction, who do not need to recruit accessory muscles to ventilate.1
Drs. Kostianev and Iluchev as well as Dr. Sankaranarayanan and colleagues point out the lack of blood-gas exchange and acute exacerbations as possible variables to be included in any index. The partial pressures of arterial oxygen and carbon dioxide were measured in the first 207 patients in our study and found to be independent predictors of the risk of death. However, they failed to improve the model in the multivariable analysis. My coauthors and I omitted this information from the final version of the manuscript to keep it within space limitations. We have found the BODE index to be an excellent predictor of the use of health resources and of exacerbations.2,3 We considered exacerbation of COPD an outcome rather than a defining variable, in the same way that myocardial infarction is an outcome of coronary artery disease and not one of its determinants. However, it is very likely that the presence of recurrent exacerbations could be a marker of poor outcome.4
Dr. Sankaranarayanan and colleagues correctly indicate that the BODE index was not evaluated in an inception cohort and therefore cannot be generalized to all patients with COPD. We agree with that epidemiologic statement but would like to point out that the index was developed for clinicians who, when examining patients, need simple tools that can help them better pinpoint the severity of the disease.
We are extremely pleased with the potential use of the BODE index in the timing of lung transplantation, as suggested by Drs. Ussetti and Laporta. Indeed, at similar FEV1 values, patients with higher BODE scores carry a worse prognosis than those with lower scores and may very well need to undergo transplantation earlier. Along with the use of the BODE index in many other possible therapeutic interventions and their comparisons, this would be an exciting use of this tool.
Bartolome R. Celli, M.D.
Caritas St. Elizabeth's Medical Center
Boston, MA 02135
References
Roussos C, Macklem PT. The respiratory muscles. N Engl J Med 1982;307:786-797.
Marin JM, Alonso J, Sanchez A, et al. Value of current COPD classification versus a multiple component staging system (SCORE) as predictor of health care resource utilization. Am J Respir Crit Care Med 2002;165:A43.abstract.
Cote CG, Marin JM, Celli BR. Factors that predict health care resources utilization (HCUR) in COPD. Am J Respir Crit Care Med 1999;159:Suppl:A912-A912. abstract.
Seemungal TAR, Donaldson GC, Paul EA, Bestall JC, Jeffries DJ, Wedzicha JA. Effect of exacerbation on quality of life in patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med 1998;157:1418-1422.