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Chronic obstructive pulmonary disease in the older adult: what defines abnormal lung function?
  1. David M Mannino1,
  2. A Sonia Buist2,
  3. William M Vollmer3
  1. 1Division of Pulmonary, Critical Care and Sleep Medicine, University of Kentucky Medical Center, Lexington, Kentucky, USA
  2. 2Department of Medicine, Oregon Health and Science University, Portland, Oregon, USA
  3. 3Kaiser Permanente Center for Health Research, Portland, Oregon, USA
  1. Correspondence to:
    Dr D M Mannino
    Division of Pulmonary and Critical Care Medicine, University of Kentucky Medical Center, 740 S Limestone, K-528, Lexington, KY 40536, USA; dmannino{at}uky.edu

Abstract

Background: The Global Initiative on Obstructive Lung Disease stages for chronic obstructive pulmonary disease (COPD) uses a fixed ratio of the post-bronchodilator forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) of 0.70 as a threshold. Since the FEV1/FVC ratio declines with age, using the fixed ratio to define COPD may “overdiagnose” COPD in older populations.

Objective: To determine morbidity and mortality among older adults whose FEV1/FVC is less than 0.70 but more than the lower limit of normal (LLN).

Methods: The severity of COPD was classified in 4965 participants aged ⩾65 years in the Cardiovascular Health Study using these two methods and the age-adjusted proportion of the population who had died or had a COPD-related hospitalisation in up to 11 years of follow-up was determined.

Results: 1621 (32.6%) subjects died and 935 (18.8%) had at least one COPD-related hospitalisation during the follow-up period. Subjects (n = 1134) whose FEV1/FVC fell between the LLN and the fixed ratio had an increased adjusted risk of death (hazard ratio (HR) 1.3, 95% CI 1.1 to 1.5) and COPD-related hospitalisation (HR 2.6, 95% CI 2.0 to 3.3) during follow-up compared with asymptomatic individuals with normal lung function.

Conclusion: In this cohort, subjects classified as “normal” using the LLN but abnormal using the fixed ratio were more likely to die and to have a COPD-related hospitalisation during follow-up. This suggests that a fixed FEV1/FVC ratio of <0.70 may identify at-risk patients, even among older adults.

  • BMI, body mass index
  • CHS, Cardiovascular Health Study
  • COPD, chronic obstructive pulmonary disease
  • FEV1, forced expiratory volume in 1 second
  • FVC, forced vital capacity
  • GOLD, Global Initiative on Obstructive Lung Disease
  • LLN, lower limit of normal

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Footnotes

  • Published Online First 7 November 2006

  • Funding: None.

  • Competing interests: None declared.

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