Comparison of clinical characteristics of chronic cough due to non‐acid and acid gastroesophageal reflux

Background and Objective Little is known about non‐acid gastroesophageal reflux‐induced chronic cough ( GERC ). The purpose of the study is to explore the clinical characteristics of non‐acid GERC . Methods Clinical symptoms, cough symptom score, capsaicin cough sensitivity, gastroesophageal reflux diagnostic questionnaire ( GerdQ ) score, findings of multichannel intraluminal impedance‐ pH monitoring ( MII ‐ pH ) and response to pharmacological anti‐reflux therapy were retrospectively reviewed in 38 patients with non‐acid GERC and compared with those of 49 patients with acid GERC . Results Non‐acid GERC had the similar cough character, cough symptom score, and capsaicin cough sensitivity to acid GERC . However, non‐acid GERC had less frequent regurgitation (15.8% vs 57.1%, χ 2  = 13.346, P  = 0.000) and heartburn (7.9% vs 32.7%, χ 2  = 7.686, P   = 0.006), and lower GerdQ score (7.4 ± 1.4 vs 10.6 ± 2.1, t  = −6.700, P  = 0.003) than acid GERC . Moreover, MII ‐ pH revealed more weakly acidic reflux episodes, gas reflux episodes and a higher symptom association probability ( SAP ) for non‐acid reflux but lower DeMeester score, acidic reflux episodes and SAP for acid reflux in non‐acid GERC than in acid GERC . Non‐acid GERC usually responded to the standard anti‐reflux therapy but with delayed cough resolution or attenuation when compared with acid GERC . Fewer patients with non‐acid GERC needed an augmented acid suppressive therapy or treatment with baclofen. Conclusions There are some differences in the clinical manifestations between non‐acid and acid GERC , but MII ‐ pH is essential to diagnose non‐acid GERC .