TY - JOUR T1 - sGaw as an alternative for FEV1 in the measurement of airway responsiveness to methacholine in patients experiencing chronic cough JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - p1189 AU - Remco Boksem AU - Maria Habes AU - Reindert van Steenwijk Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/p1189.abstract N2 - Background: A drop of 50% in specific airway conductance (sGaw) during a methacholine challenge test (MCT) is considered to be comparable to a drop of 20% in FEV1 to asses airway hyperresponsiveness (AHR). In our department patients with chronic cough tested with a MCT on a drop of FEV1 show an increase in cough without reaching a conclusive PC20.Aim: To examine the correlation between drops in FEV1 and sGaw during MCT in chronic cough patients.Methods: 16 patients with history of chronic cough were included for a cross-sectional study. Inclusion criteria: episodic chest symptoms, chronic cough and post bronchodilator FEV1/FVC ratio ≥ 0.70. Each concentration in MCT was followed by measurement of sGaw and FEV1. Linear regression was used to determine the correlation between PC20FEV1 and PC50sGaw.Results: LogPC50sGaw was significantly lower than log PC20FEV1 p=0,004.7 patients showed a positive response only to sGaw (Figure 1).We found that a decrease of 20% in FEV1 was accompanied by 65% decrease in sGaw.Conclusions: Patients with chronic cough show a larger response to methacholine by sGaw as compared to FEV1 than reported in the literature. This suggests that in this set of patients sGaw is relatively more sensitive in assessing AHR.Implications: Chronic cough patients may exhibit AHR that remains unnoticed when performing MCT with FEV1. ER -