0
Original Research: COPD |

Variability of the Prevalence of Undiagnosed Airflow Obstruction in Smokers Using Different Diagnostic Criteria*

Arthur Chun-Wing Lau, MBBS, MRCP, FCCP; Mary Sau-Man Ip, MD, FRCP, FCCP; Christopher Kei-Wai Lai, DM, FRCP; Kah-Lin Choo, FRCP, FCCP; Kam-Shing Tang, MBBS, MRCP; Loretta Yin-Chun Yam, MBBS, FRCP, FCCP; Moira Chan-Yeung, MBBS, FRCP, FCCP
Author and Funding Information

*From the Department of Intensive Care (Dr. Lau), Division of Respiratory and Critical Care Medicine (Dr. Yam), Department of Medicine, Pamela Youde Nethersole Eastern Hospital; University Department of Medicine (Drs. Ip and Chan-Yeung), The University of Hong Kong, Queen Mary Hospital; The Chinese University of Hong Kong (Dr. Lai); Department of Medicine (Dr. Choo), North District Hospital, Hong Kong; and Intensive Care Unit (Dr. Tang), Tuen Mun Hospital, Hong Kong, SAR, China.

Correspondence to: Mary Sau-Man Ip, MD, FRCP, FCCP, Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong SAR, China; e-mail: msmip@hkucc.hku.hk



Chest. 2008;133(1):42-48. doi:10.1378/chest.07-1434
Text Size: A A A
Published online

Purpose: To estimate the prevalence of undiagnosed airflow obstruction (AFO) in Hong Kong smokers with no previous diagnosis of respiratory disease, and to assess its variability when applying different prediction equations and diagnostic criteria.

Methods: A multicenter, population-based, cross-sectional prevalence study was performed in smokers aged 20 to 80 years. Three different criteria (fixed 70% [Global Initiative for Chronic Obstructive Lung Disease and British Thoracic Society], fixed 75%, and European Respiratory Society [ERS]) were applied to define a lower limit of normal (LLN) of the FEV1/FVC ratio to compare with the Hong Kong Chinese reference equation (criterion 1), which had used a distribution-free method to obtain the lower fifth percentile of FEV1/FVC ratio as the LLN.

Results: In 525 male patients, using criterion 1 (local internal prediction equation) and defining AFO as FEV1/FVC less than LLN, the overall prevalence of AFO was 13.7%: 8.3% in age ≥ 20 to 40 years, 14.0% in age ≥ 40 to 60 years, and 17.8% in age ≥ 60 to 80 years. When the local internal prediction equation was used as the comparison reference, the fixed-ratio methods tended to miss AFO in younger age groups and overdiagnose AFO in old age, while the ERS criteria, which uses an almost lower fifth percentile-equivalent method, showed less of such a trend but still only showed moderate agreement with criterion 1.

Conclusions: Undiagnosed AFO was prevalent in Hong Kong smokers. Estimated prevalence rates were highly affected by the criteria used to define AFO. The predicted lower fifth percentile values calculated from a local reference equation as the LLN of FEV1/FVC ratio should be used for the diagnosis of AFO.

Figures in this Article

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Figures

Tables

References

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.

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Related Content

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

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