External validation of a chronic obstructive pulmonary disease diagnostic questionnaire

¹ Dept of General Practice; and Care and Public Health Research Institute (CAPHRI), Maastricht University
² Dept of Epidemiology; and Care and Public Health Research Institute (CAPHRI), Maastricht University
³ Dept of Respiratory Medicine, Maastricht University Hospital. Maastricht, The Netherlands; and Care and Public Health Research Institute (CAPHRI), Maastricht University

^* To whom correspondence should be addressed. E-mail: d.kotz{at}hag.unimaas.nl.

	Abstract

The aim of the present study was to determine the external validity of a recently developed questionnaire for identifying patients at increased risk of airflow limitation in smokers from the general population in Dutch- and Belgian-Limburg.

As part of a study on early detection of airflow limitation and subsequent smoking cessation treatment (ISRCTN 64481813), the COPD diagnostic questionnaire developed by PRICE et al. was used in current smokers aged 40–70 years, with a smoking history of 10 or more pack years, who reported one or more respiratory symptoms (cough, sputum production, or dyspnoea) but who had no diagnosis of a respiratory disease (COPD, asthma). Spirometry according to ATS/ERS criteria served as a reference test.

Six hundred seventy-six subjects entered the analyses. Of these, 398 had normal lung function and 278 had a diagnosis of COPD (post-bronchodilator FEV₁/FVC<0.70). The ability of the COPD diagnostic questionnaire to discriminate between subjects with and without COPD was poor: ROC_AUC=0.65.

In a high risk population consisting of middle-aged current smokers with more than 10 pack years, the COPD diagnostic questionnaire is probably not useful as a diagnostic tool to identify patients with an increased risk of airflow limitation.