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Mayo Clin Proc. 2011 May;86(5):375-81. doi: 10.4065/mcp.2010.0787.

Prevalence of airway obstruction assessed by lung function questionnaire.

Author information

1
Department of Medicine, George Washington University School of Medicine, Washington, DC, USA.

Abstract

OBJECTIVE:

To estimate the prevalence of unidentified chronic obstructive pulmonary disease (COPD) and determine the screening accuracy of the Lung Function Questionnaire (LFQ).

PATIENTS AND METHODS:

Cigarette smokers who had a smoking history of 10 or more pack-years and were aged 30 years or older were recruited from 36 centers from February 18, 2009, to May 29, 2009. A total of 1575 patients completed a Web-based survey including the 5-item LFQ. Spirometry was performed on patients with an LFQ total score of 18 or less and on a subset scoring more than 18. The primary outcome was the proportion of patients at risk of airflow obstruction as measured by the LFQ (score, ≤ 18) in whom an airflow obstruction was confirmed by spirometry.

RESULTS:

Of the patients who completed the LFQ, 849 (54%) had standardized spirometry data available. On the basis of LFQ and spirometry results, the estimated prevalence of possible COPD was 17.9% (95% confidence interval, 15.3%-20.6%). At a cut point of 18 or less, sensitivity, specificity, positive predictive value, and negative predictive value of the LFQ were 88%, 25%, 21%, and 90%, respectively. Approximately 1 in 5 patients (21%) aged 30 years or older and 1 in 4 (26%) aged 50 years or older scored 18 or less on the LFQ and had a ratio of forced expiratory volume in the first second of expiration to forced vital capacity less than 0.70.

CONCLUSION:

On the basis of postbronchodilator spirometry results using weighted estimates, approximately 1 in 5 patients (21%) aged 30 years or older with a smoking history of 10 or more pack-years seen in a primary care setting is likely to have COPD. The LFQ could be a helpful COPD case-finding tool for clinicians to identify patients who need further evaluation.

TRIAL REGISTRATION:

clinicaltrials.gov Identifier: NCT01013948.

PMID:
21531880
PMCID:
PMC3084639
DOI:
10.4065/mcp.2010.0787
[Indexed for MEDLINE]
Free PMC Article

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