BODE plus DOSE plus Pa O 2 equals DO RE MI BOX?

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AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE

Division of Respiratory Disease Studies National Institute for Occupational Safety and Health Morgantown, West Virginia References 1. Neupane B, Jerrett M, Burnett RT, Marrie T, Arian A, Leob M. Longterm exposure to ambient air pollution and risk of hospitalization with community-acquired pneumonia in older adults. Am J Respir Crit Care Med 2010;181:47–53. 2. Palmer KT, Poole J, Ayres JG, Mann J, Burge PS, Goggon D. Exposure to metal fume and infectious pneumonia. Am J Epidemiol 2003; 157:227–233. 3. Valavandis A, Salika A, Theodoropoulou A. A generation of hydroxyl radicals by urban suspended particulate matter: the role of iron. Atmos Environ 2000;34:2379–2386. 4. Smith KR, Varant JM, Hu AA, Lighty JS, Aust AE. Interlukin-8 level in human lung epithelial cells are increased in response to coal fly ash and vary with the bioavailability of iron, as a function of particle size and source of coal. Chem Res Toxicol 2000;13:118–125. 5. Weinberg ED. Modulation of intramacrophage iron metabolism during microbial cell invasion. Microbes Infect 2000;1:1–5. 6. Helleday R, Huberman D, Blomberg A. Stjernberg, Sandstro¨m T. Nitrogen dioxide exposure impairs the frequency of the mucociliary activity in healthy subjects. Eur Respir J 1995;8:1664–1668. 7. Schlesinger RB, Driscoll KE, Neumann BD, Vollmuth TA. Particle clearance from the lungs: assessment of effects due to inhaled irritants. Ann Occup Hyg 1988;32:113–123. 8. Rosenstock L, Cullen MR, Brodkin CA, Redlich CA. Clinical occupational and environmental medicine, 2nd ed. Philadelphia: Elsevier Saunders; 2005. Pp. 352 and 376.

From the Authors:

We agree with Drs. Hnizdo and Storey that the positive association between a history of regular exposure to gases, fumes, or chemicals at work and hospitalization, as well as smoking, for community-acquired pneumonia was striking (1). Drs. Hniizdo and Storey rightly draw attention to important occupational health associations that we found. Although these findings are intriguing, we caution that the history of these exposures was based on self-reports and was not externally validated. Hnizdo and Storey postulate that permanent lung damage due to occupational exposure could potentiate the effect of N02 and PM (2, 3); however, we did not find an interaction between occupational exposure and environmental pollution. We believe that our findings support the need for cohort studies of community-acquired pneumonia that prospectively record and validate occupational health exposures and utilize biomarkers to help determine causative mechanisms. Author Disclosure: M.L. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript. B.N. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript. M.J. has received consultancy fees from Health Canada ($5,001–$10,000).

MARK LOEB, M.D., M.SC. BINOD NEUPANE, M.SC. Department of Medicine, Pathology, and Molecular Medicine and Department of Clinical Epidemiology and Biostatistics McMaster University Hamilton, Ontario, Canada MICHAEL JERRETT, PH.D. Division of Environmental Health Sciences School of Public Health University of California Berkeley, California

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VOL 182

2010

References 1. Neupane B, Jerrett M, Burnett RT, Marrie T, Arian A, Leob M. Longterm exposure to ambient air pollution and risk of hospitalization with community-acquired pneumonia in older adults. Am J Respir Crit Care Med 2010;181:47–53. 2. Helleday R, Huberman D, Blomberg A. Stjernberg, Sandstro¨m T. Nitrogen dioxide exposure impairs the frequency of the mucociliary activity in healthy subjects. Eur Respir J 1995;8:1664–1668. 3. Schlesinger RB, Driscoll KE, Neumann BD, Vollmuth TA. Particle clearance from the lungs: assessment of effects due to inhaled irritants. Ann Occup Hyg 1988;32:113–123.

BODE plus DOSE plus PaO2 equals DO RE MI BOX? To the Editor:

Jones and colleagues (1) are to be congratulated on their almost perfect design, statistics, and validation procedures for the DOSE Index: a composite index of severity in chronic obstructive pulmonary disease (COPD). After the BODE index of Celli and colleagues (2), other multidimensional staging systems for COPD with catchy names have entered the spiraling cloning race. None of these are perfect, though, and this raises a serious issue with respect to the article by Jones and coworkers. In our article (3) we argued that the ‘‘ideal’’ composite index for assessment of patients with COPD should contain at least two characteristics complementary to the proposed DO RE MI BOX: smoking habits (the causal link between the smoking and COPD progression is beyond doubt) and patients’ age (because of the increased co-morbidity); or, as an alternative, a combined comorbidity index (4). In another study (5) we found that patients with COPD with frequent exacerbations in a previous year have a significantly higher BODE score than those experiencing infrequent exacerbations (. or , 2.3 per year). And this is an accomplishment which, much to our regret, we failed to find in the remarkable article by Jones and colleagues. Research should give green light to all original ideas and none should be a priori rejected on the strength of being generated in the so-called unprivileged countries. Author Disclosure: Neither author has a financial relationship with a commercial entity that has an interest in the subject of this manuscript.

STEFAN KOSTIANEV, M.D., PH.D., D.M.SC. VLADIMIR HODGEV, M.D., PH.D. University of Medicine Plovdiv, Bulgaria

References 1. Jones RC, Donaldson GC, Chavannes NH, Kida K, Dickson-Spillmann M, Harding S, Wedzicha JA, Price D, Hyland ME. Derivation and validation of a composite index of severity in chronic obstructive pulmonary disease: the DOSE Index. Am J Respir Crit Care Med 2009;180:1189–1195. 2. Celli BR, Cote CG, Marin JM, Casanova C, Montes de Oca M, Mendez RA, Pinto Plata V, Cabral HJ. The body-mass index, airflow obstruction, dyspnea, and exercise capacity index in chronic obstructive pulmonary disease. N Engl J Med 2004;350:1005–1012. 3. Kostianev SS, Hodgev VA, Iluchev DH. Multidimensional system for assessment of COPD patients: comparison with BODE index. Folia Med (Plovdiv) 2008;50:29–38. 4. Charlson M, Szatrowski T, Peterson J, Gold J. Validation of a combined comorbidity index. J Clin Epidemiol 1994;47:1245–1251. 5. Hodgev VA, Kostianev SS, Marinov BI. Correlation of frequency of exacerbations with the BODE index in COPD patients. Folia Med (Plovdiv) 2006;48:18–22.