Validation of a questionnaire to screen chronic obstructive respiratory diseases

<sec><title>BACKGROUND</title>Spirometry is the gold standard for diagnosing chronic obstructive respiratory diseases (CORD), but it is not widely available in primary healthcare in Vietnam. We aimed to validate a simple CORD Screening Questionnaire (CORD-SQ) for the Vietnamese population to screen subjects requiring spirometry.</sec><sec><title>METHODS</title>In a cross-sectional study, 589 volunteers seen in a primary healthcare unit were submitted to the CORD-SQ. This questionnaire included four items (cumulative smoking, history of tuberculosis, current breathlessness and wheezing or whistling) with a total score ranging from 0 to 6. The cut-off point of the CORD-SQ was previously determined as a predictor of CORD, which was last defined by spirometry (forced expiratory volume in 1 second/forced vital capacity < lower limit of normal) measured in each subject.</sec><sec><title>RESULTS</title>The prevalence of CORD was 10% among the 517 subjects with non-asthmatic history. With a cut-off point of 2 for the CORD-SQ, the sensitivity and specificity were 69% and 91%, respectively, with a 46% positive predictive value and 94% negative predictive value. The area under the receiver operating characteristic curve of the CORD-SQ to discriminate the CORD was 0.83 (95% CI 0.75-0.90).</sec><sec><title>CONCLUSION</title>In the non-asthmatic Vietnamese primary health care population, the simple CORD-SQ efficiently identifies the people at risk of CORD, requiring spirometry.</sec>.