TY - JOUR T1 - Exhaled NO may predict loss of asthma control: the effect of concomitant allergic rhinitis JF - European Respiratory Journal JO - Eur Respir J SP - 1006 LP - 1007 DO - 10.1183/09031936.00065209 VL - 34 IS - 4 AU - A. I. Papaioannou AU - M. Minas AU - K. Tanou AU - K. I. Gourgoulianis AU - K. Kostikas Y1 - 2009/10/01 UR - http://erj.ersjournals.com/content/34/4/1006.abstract N2 - To the Editors: We read with great interest the recent article by Michils et al. 1 demonstrating that sequential changes in exhaled NO fraction (FeNO) are associated with asthma control, even in smokers who present lower levels of FeNO compared to nonsmokers. Besides tobacco smoking, we have recently shown that a significant confounding factor in the diagnosis of asthma using FeNO is the presence of allergic rhinitis, since patients with allergic rhinitis have been found to have elevated FeNO levels [2]. This effect may well be attributed to the underlying atopic status of those patients, since elevated FeNO has been shown to be associated with a phenotype characterised by atopy and increased airway responsiveness [3]. In the present study we attempted to evaluate whether the coexistence of allergic rhinitis may affect the validity of sequential changes of FeNO in predicting control in asthmatic patients. We performed a post-hoc analysis of a prospectively collected database of all consecutive patients evaluated in the Asthma Clinic of the Respiratory Medicine Dept, University of Thessaly Medical School (Larissa, Greece), between … ER -