Sarah Lewis|Scott T. Weiss|John Britton
Airway responsiveness and peak flow variability in the diagnosis of asthma for epidemiological studies
Respiratory Clinical Trials|University of Nottingham|Brigham and Women's Hospital|Respiratory Clinical Trials|University of Nottingham
airway responsiveness variability peak expiratory flow pef widely used objective diagnostic measures asthma clear variables calculated adjusted obtain highest diagnostic validity physiciandiagnosed asthma communitydata communitybased sample 1513 adults usedairway responsiveness methacholine 7day pef data obtained 1991 asthma respiratory symptoms diagnosed questionnaires 1991 1999airway responsiveness expressed provocative dose causing 20 fall forced expiratory volume one second pd20 twopoint leastsquares regression slopespef variability expressed daily amplitude weekly standard deviation mean two lowest readingscontinuous measures adjusted measures baseline airway calibre linear regressionmeasures airway responsiveness greater sensitivity specificity selfreported diagnosed asthma expressions pef variability adjustment airway calibrediagnostic validity substantially better adults aged v50 yrs pd20 provided best sensitivity specificity 61 95 83 mmolin aged o50 yrs measure closely related diagnosed asthmain younger age groups provocative dose causing 20 fall forced expiratory volume one second provides valuable objective measure asthma epidemiological studies unable distinguish asthma chronic obstructive pulmonary disease older people