The importance of maximal airway response to methacholine in the prediction of asthma development in patients with allergic rhinitis
Article first published online: 30 MAY 2002
Clinical & Experimental Allergy
Volume 32, Issue 6, pages 921–927, June 2002
How to Cite
Koh, Y. Y., Kang, E. K., Min, Y.-G. and Kim, C. K. (2002), The importance of maximal airway response to methacholine in the prediction of asthma development in patients with allergic rhinitis. Clinical & Experimental Allergy, 32: 921–927. doi: 10.1046/j.1365-2222.2002.01399.x
- Issue published online: 30 MAY 2002
- Article first published online: 30 MAY 2002
- Submitted 30 July 2001; revised 26 October 2001; accepted 29 January 2002
- allergic rhinitis;
- airway hyper-responsiveness;
- maximal airway response;
Background Allergic rhinitis is a known predictor and correlate of asthma incidence. However, it is not clear which patients with allergic rhinitis are at greater risk of the development of asthma.
Objective The aim of this study was to investigate whether airway hypersensitivity and/or increased maximal response on the dose–response curve to methacholine would predict the development of asthma in subjects with allergic rhinitis.
Methods One hundred and forty-one children with allergic rhinitis were prospectively studied for 7 years. At the initiation of the study, bronchial provocation test with methacholine using a stepwise increasing concentration technique was performed to measure PC20 (provocative concentration causing a 20% fall in FEV1) and maximal response. Each subject was evaluated at least every 6 months and details of asthmatic symptoms or signs experienced during the intervening period were taken.
Results Twenty of 122 subjects available for the follow-up developed asthma. Nine (19.6%) of 46 hypersensitive (PC20 < 18 mg/mL) subjects developed asthma, compared with 11 (14.5%) of 76 normosensitive subjects (P = 0.462). Eight (32%) of 25 subjects without maximal response plateau developed asthma, compared with 12 (12.4%) of 97 subjects with maximal response plateau (P = 0.018). Score test for trend revealed a significant association between the level of maximal response (P = 0.007), but not the degree of methacholine PC20 (P = 0.123), and the future development of asthma.
Conclusion An increased maximal airway response to methacholine is shown to be a better predictor for the future development of asthma in patients with allergic rhinitis, than airway hypersensitivity to methacholine.