Identification of adults with symptoms suggestive of obstructive airways disease: Validation of a postal respiratory questionnaire
1 North West Lung Research Centre, General Practice Research Unit, North West Lung Research Centre, Wythenshawe Hospital, Southmoor Rd, Manchester, M23 9LT, UK
2 University of Aberdeen, Department of General Practice & Primary Care, Foresterhill Health Centre, Westburn Road, Aberdeen AB25 2AY, UK
3 University of Manchester, Biostatistics Group, School of Epidemiology and Health Sciences, Oxford Road, Manchester M13 9PL, UK
BMC Family Practice 2003, 4:5 doi:10.1186/1471-2296-4-5Published: 25 April 2003
Two simples scoring systems for a self-completed postal respiratory questionnaire were developed to identify adults who may have obstructive airways disease. The objective of this study was to validate these scoring systems.
A two-stage design was used. All adults in two practice populations were sent the questionnaire and a stratified random sample of respondents was selected to undergo full clinical evaluation. Three respiratory physicians reviewed the results of each evaluation. A majority decision was reached as to whether the subject merited a trial of obstructive airways disease medication. This clinical decision was compared with two scoring systems based on the questionnaire in order to determine their positive predictive value, sensitivity and specificity.
The PPV (positive predictive value) of the first scoring system was 75.1% (95% CI 68.6–82.3), whilst that of the second system was 82.3% (95% CI 75.9–89.2). The more stringent second system had the greater specificity, 97.1% (95% CI 96.0–98.2) versus 95.3% (95% CI 94.0–96.7), but poorer sensitivity 46.9% (95% CI 33.0–66.8) versus 50.3% (95% CI 35.3–71.6).
This scoring system based on the number of symptoms/risk factors reported via a postal questionnaire could be used to identify adults who would benefit from a trial of treatment for obstructive airways disease.