Airway hyperresponsiveness to mannitol and methacholine and exhaled nitric oxide: A random-sample population study - 07/08/11
Abstract |
Background |
Studies of selected patient groups have shown that airway hyperresponsiveness (AHR) to mannitol is more specific than methacholine for the diagnosis of asthma, as well as more closely associated with markers of airway inflammation in asthma.
Objective |
We sought to compare AHR to mannitol and methacholine and exhaled nitric oxide (eNO) levels in a nonselected population sample.
Methods |
In 238 young adults randomly drawn from the nationwide civil registration list in Copenhagen, Denmark, AHR to mannitol and methacholine, as well as levels of eNO, were determined, and the association with asthma was analyzed.
Results |
In diagnosing asthma the specificity of methacholine and mannitol was 80.2% (95% CI, 77.1% to 82.9%) and 98.4% (95% CI, 96.2% to 99.4%), respectively, with a positive predictive value of 48.6% versus 90.4%, whereas the sensitivity was 68.6% (95% CI, 57.1% to 78.4%) and 58.8% (95% CI, 50.7% to 62.6%), respectively. In asthmatic subjects AHR to mannitol was associated with increased eNO levels (positive AHR to mannitol: median, 47 ppb [interquartile range, 35-68 ppb]; negative AHR to mannitol: median, 19 ppb [interquartile range, 13-30 ppb]; P = .001), whereas this was not the case for AHR to methacholine (median of 37 ppb [interquartile range, 26-51 ppb] vs 24 ppb [interquartile range, 15-39 ppb], P = .13).
Conclusion |
In this random population sample, AHR to mannitol was less sensitive but more specific than methacholine in the diagnosis of asthma. Furthermore, AHR to mannitol was more closely associated with ongoing airway inflammation in terms of increased eNO levels.
Le texte complet de cet article est disponible en PDF.Key words : Asthma, airway hyperresponsiveness, mannitol, methacholine, diagnosis, exhaled nitric oxide, inflammation, epidemiology, population
Abbreviations used : AHR, BPT, eNO, IQR, RDR, ROC
Plan
The Danish Agency for Science, Technology and Innovation, an institution under the Danish Ministry of Science, Technology and Innovation, supported the study with a 1-year scholarship. Pharmaxis provided the research team with an unrestricted grant, with which one of the research assistants was employed. Moreover, mannitol test kits were provided by Pharmaxis Ltd (Frenchs Forest, NSW, Australia). |
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Disclosure of potential conflict of interest: C. Porsbjerg receives honoraria from Pharmaxis and receives research funding for the Danish Agency of Science and Technology. The rest of the authors have declared that they have no conflict of interest. |
Vol 126 - N° 5
P. 952-958 - novembre 2010 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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