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Correspondence |

Abandoning FEV1/FVC < 0.70 to Detect Airway Obstruction: An Essential Debate but With the Right Emphasis? FREE TO VIEW

Bas Robberts, MD; Tjard Schermer, PhD
Author and Funding Information

From the Department of Primary and Community Care, Radboud University Nijmegen Medical Centre.

Correspondence to: Tjard Schermer, PhD, Radboud University Nijmegen Medical Centre, Department of Primary and Community Care (117-ELG), PO Box 9101, 6500 HB Nijmegen, The Netherlands; e-mail: t.schermer@elg.umcn.nl


Financial/nonfinancial disclosures: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (http://www.chestpubs.org/site/misc/reprints.xhtml).


© 2011 American College of Chest Physicians


Chest. 2011;139(5):1253-1254. doi:10.1378/chest.10-3099
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To the Editor:

In recent Point/Counterpoint Editorials in CHEST (November 2010), Drs Celli and Halbert1 argue in favor of and Drs Enright and Brusasco2 argue against using the fixed cutpoint for FEV1/FVC < 0.70 to define airflow obstruction when diagnosing COPD. This is clearly an important debate, but we believe that the authors fail to address some essential points in their respective contributions.

They base their arguments mainly on issues related to other conditions (ie, hypertension), detection of obstruction in the general population, comparison of prevalence figures between countries, underdiagnosis of COPD, and population-level evidence regarding FEV1/FVC decline with age.1,2 However, in our view, the debate about the preference for the 0.70 or an age- and sex-specific FEV1/FVC cutpoint should focus on the consequences of this choice when diagnosing individuals.

Primary care physicians (PCPs) are often the first health-care professionals that people will turn to when they experience respiratory symptoms. Thus, in many cases it will be the PCP who needs to decide whether the symptoms are caused by COPD or by one of the many other causes for the patient’s symptoms.3 Availability of spirometry is indeed increasing in many countries, and PCPs will often need to interpret the spirometry results, even though they are not respiratory experts. By stating that “it is the evaluating physician who ultimately decides the medical significance of an abnormal value in a specific patient encounter,” Drs Celli and Halbert1 do seem to recognize this, but at the same time they cast doubt on PCPs’ ability to judge the significance of an abnormal value for the FEV1/FVC (“It can be easily understood by clinicians, lowering some of the barriers to spirometry.”).

The best thing we can do to support PCPs in deciding whether an FEV1/FVC value is medically significant in a particular patient is to provide them with cutpoints that leave no indefiniteness about the role age, sex, and race have in the interpretation of the patient’s spirometry test. We have recently shown that using lower limit of normal (LLN) cutpoints instead of FEV1/FVC < 0.70 substantially reduces the number of false-positive interpretations in primary care, especially in elderly subjects (Fig 1).4 We agree with Drs Enright and Brusasco2 that switching to LLN cutpoints does not need to be that complicated, as most electronic spirometers already incorporate LLN equations, and even if they do not, a simple table or graphical aid—which is no more difficult to read than growth charts for children—could solve this.

Figure Jump LinkFigure 1. Association between FEV1/FVC and age in male symptomatic current and ex-smokers aged ≥ 50 years referred for spirometric testing by their primary care physician (n = 3,473). The horizontal red line indicates the fixed 0.70 FEV1/FVC cutoff point that is currently recommended by all major clinical COPD guidelines; the black diagonal line indicates the lower limit of normal for healthy nonsmoking men. Black circles = true negatives; green circles = true positives (unique subjects considered to have airflow obstruction according to both definitions); red circles = false positives (subjects in whom discordant conclusions regarding the presence of airflow obstruction are drawn, n = 558, 16% of all subjects). (Adapted with permission from Schermer et al.4)Grahic Jump Location

From a research point of view, the million-dollar question is whether a middle-aged or elderly subject who has an LLN < FEV1/FVC < 0.70 when being evaluated for possible COPD actually shows abnormal progression of airflow obstruction or other clinical features that justify a COPD diagnosis. Currently, there is insufficient evidence to answer this question. We are very interested to learn the responses of the authors on these points.

Celli BR, Halbert RJ. Point: should we abandon FEV1/FVC <0.70 to detect airway obstruction? No. Chest. 2010;1385:1037-1040. [CrossRef] [PubMed]
 
Enright P, Brusasco V. Counterpoint: should we abandon FEV1/FVC <0.70 to detect airway obstruction? Yes. Chest. 2010;1385:1040-1042. [CrossRef] [PubMed]
 
Hoogendoorn M, Feenstra TL, Schermer TR, Hesselink AE, Rutten-van Mölken MP. Severity distribution of chronic obstructive pulmonary disease (COPD) in Dutch general practice. Respir Med. 2006;1001:83-86. [CrossRef] [PubMed]
 
Schermer TR, Smeele IJ, Thoonen BP, et al. Current clinical guideline definitions of airflow obstruction and COPD overdiagnosis in primary care. Eur Respir J. 2008;324:945-952. [CrossRef] [PubMed]
 

Figures

Figure Jump LinkFigure 1. Association between FEV1/FVC and age in male symptomatic current and ex-smokers aged ≥ 50 years referred for spirometric testing by their primary care physician (n = 3,473). The horizontal red line indicates the fixed 0.70 FEV1/FVC cutoff point that is currently recommended by all major clinical COPD guidelines; the black diagonal line indicates the lower limit of normal for healthy nonsmoking men. Black circles = true negatives; green circles = true positives (unique subjects considered to have airflow obstruction according to both definitions); red circles = false positives (subjects in whom discordant conclusions regarding the presence of airflow obstruction are drawn, n = 558, 16% of all subjects). (Adapted with permission from Schermer et al.4)Grahic Jump Location

Tables

References

Celli BR, Halbert RJ. Point: should we abandon FEV1/FVC <0.70 to detect airway obstruction? No. Chest. 2010;1385:1037-1040. [CrossRef] [PubMed]
 
Enright P, Brusasco V. Counterpoint: should we abandon FEV1/FVC <0.70 to detect airway obstruction? Yes. Chest. 2010;1385:1040-1042. [CrossRef] [PubMed]
 
Hoogendoorn M, Feenstra TL, Schermer TR, Hesselink AE, Rutten-van Mölken MP. Severity distribution of chronic obstructive pulmonary disease (COPD) in Dutch general practice. Respir Med. 2006;1001:83-86. [CrossRef] [PubMed]
 
Schermer TR, Smeele IJ, Thoonen BP, et al. Current clinical guideline definitions of airflow obstruction and COPD overdiagnosis in primary care. Eur Respir J. 2008;324:945-952. [CrossRef] [PubMed]
 
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