0
Correspondence |

ObesityObesity and FEV1/FVC Ratio When Diagnosing COPD: Another Good Reason to Question the Fixed FEV1/FVC Ratio When Diagnosing COPD FREE TO VIEW

Lisette van den Bemt, PhD; Tjard Schermer, PhD
Author and Funding Information

From the Department of Primary and Community Care, Centre for Family Medicine, Geriatric Care and Public Health, Radboud University Nijmegen Medical Centre.

Correspondence to: Lisette van den Bemt, PhD, Department of Primary and Community Care, Centre for Family Medicine, Geriatric Care and Public Health, Radboud University Nijmegen Medical Centre (Route 117), PO Box 9101, 6500 HB Nijmegen, The Netherlands; e-mail: L.vandenbemt@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).


© 2012 American College of Chest Physicians


Chest. 2012;141(2):568-569. doi:10.1378/chest.11-2056
Text Size: A A A
Published online

For every complex problem, there is a simple solution that is wrong.

         G.B. Shaw

To the Editor:

The obesity epidemic does not pass by our (also growing) population of COPD patients. In their recent article in CHEST (August 2011), O’Donnell and coworkers1 analyzed the lung volumes of adult subjects who visited their lung function laboratory and who suffered from airflow obstruction based on the GOLD (Global Initiative for Chronic Obstructive Lung Disease) criterion (postbronchodilator FEV1/FVC <0.7). One of their main conclusions was that the FEV1/FVC ratio is strongly influenced by the lung-volume-reducing effect of increasing weight. We have found similar results in earlier published data.2

So, again, we may have a problem with the use of the FEV1/FVC ratio to diagnose COPD. Not only will the use of the fixed (ie, 0.7) value of the FEV1/FVC ratio overdiagnose COPD in elderly subjects,3 it may also underdiagnose the presence of airflow obstruction in obese individuals. This is an important finding, considering the fact that 29% of O’Donnell’s study population was obese.

However, the true magnitude of this problem is likely to be underestimated in the study. The study population consisted of adults who had a postbronchodilator FEV1/FVC <0.7. If increasing weight raises the FEV1/FVC ratio, obese subjects are more likely to be wrongly classified as having no airflow obstruction and may thus have been underrepresented in the study. This is an important issue for further research.

For clinical practice, the assessment of COPD in obese patients is further complicated by the fact that dyspnea (the key symptom of COPD) may also be caused by carrying excessive body mass.4 The combination of a higher FEV1/FVC ratio and dyspnea that may also be related to obesity may easily result in underdiagnosis of COPD in obese individuals. This could lead to inadequate weight reduction treatment decisions because, according to the obesity paradox,5 patients with severe COPD may even benefit from their excessive body mass in terms of survival. Diagnosing COPD is a complex process that is further complicated by comorbid conditions like obesity, and, again, a simplified method of defining airflow obstruction based on a fixed ratio (ie, FEV1/FVC) seems inadequate.

O’Donnell DE, Deesomchok A, Lam YM, et al. Effects of BMI on static lung volumes in patients with airway obstruction. Chest. 2011;1402:461-468 [PubMed] [CrossRef]
 
van den Bemt L, van Wayenburg CA, Smeele IJ, Schermer TR. Obesity in patients with COPD, an undervalued problem? Thorax. 2009;647:640-641 [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 [PubMed]
 
Ho SF, O’Mahony MS, Steward JA, Breay P, Buchalter M, Burr ML. Dyspnoea and quality of life in older people at home. Age Ageing. 2001;302:155-159 [PubMed]
 
Landbo C, Prescott E, Lange P, Vestbo J, Almdal TP. Prognostic value of nutritional status in chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 1999;1606:1856-1861 [PubMed]
 

Figures

Tables

References

O’Donnell DE, Deesomchok A, Lam YM, et al. Effects of BMI on static lung volumes in patients with airway obstruction. Chest. 2011;1402:461-468 [PubMed] [CrossRef]
 
van den Bemt L, van Wayenburg CA, Smeele IJ, Schermer TR. Obesity in patients with COPD, an undervalued problem? Thorax. 2009;647:640-641 [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 [PubMed]
 
Ho SF, O’Mahony MS, Steward JA, Breay P, Buchalter M, Burr ML. Dyspnoea and quality of life in older people at home. Age Ageing. 2001;302:155-159 [PubMed]
 
Landbo C, Prescott E, Lange P, Vestbo J, Almdal TP. Prognostic value of nutritional status in chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 1999;1606:1856-1861 [PubMed]
 
NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543