In:
Canadian Respiratory Journal, Hindawi Limited, Vol. 17, No. 5 ( 2010), p. 224-228
Kurzfassung:
BACKGROUND: The interpretation of methacholine test results do not usually consider the symptoms for which the subject was referred and those that occur during the test. OBJECTIVE: To assess the association between methacholine test results and symptoms, and to examine variables that may affect this association. METHODS: A total of 400 prospectively chosen subjects who underwent methacholine testing for possible asthma were investigated. The subjects answered a short questionnaire regarding the symptoms for which they had been referred and those that were encountered during the methacholine test. RESULTS: The positive predictive value for the reproduction of symptoms during the test compared with symptoms for which subjects had been referred were 84% for dyspnea, 87% for cough, 81% for wheezing and 72% for chest tightness. The positive predictive value among the values obtained by measuring the provocative concentration of methacholine causing a 20% fall (PC 20 ) in forced expiratory volume in 1 s on the one hand, and specific symptoms on the other, varied by up to approximately 50%; negative predictive values were higher. Forty-eight per cent of subjects with a PC 20 of 16 mg/mL or lower reported that the test had globally reproduced their symptoms. This association was significantly stronger in women, young subjects and those taking inhaled steroids. CONCLUSIONS: The methacholine test generally reproduced the symptoms for which the subjects were referred. The absence of a specific symptom (eg, dyspnea, cough, wheezing or chest tightness), either in daily life or at the time of methacholine testing, was more generally associated with a negative test than the reverse. The global impression that the test had reproduced what the patient had experienced in daily life was significantly associated with a positive test (ie, a PC 20 of 16 mg/mL or lower), with the association being stronger in young subjects and women.
Materialart:
Online-Ressource
ISSN:
1198-2241
Sprache:
Englisch
Verlag:
Hindawi Limited
Publikationsdatum:
2010
ZDB Id:
2207107-6
