Can acid exposure time replace the DeMeester score in the diagnosis of gastroesophageal reflux-induced cough?

BACKGROUND: The objective of this study was to compare the predictive accuracy of the acid exposure time (AET) with the DeMeester score (DMS) for gastroesophageal reflux–induced cough (GERC). METHODS: A total of 277 patients who underwent multichannel intraluminal impedance pH monitoring (MII-pH) were enrolled, and their clinical information and laboratory results were retrospectively analyzed. The diagnostic value of AET for GERC was compared with that of the DMS, symptom association probability (SAP), and symptom index (SI). RESULTS: A total of 236 patients met the inclusion criteria, 150 patients (63.65%) were definitely diagnosed with GERC, including 111(74%) acid GERC and 39 (26%) nonacid GERC. The optimal cutoff value of AET for diagnosing GERC was AET > 4.8%, and its diagnostic value was equal to that of DMS > 14.7 (AUC = 0.827 versus 0.818, p = 0.519) and was superior to that of SAP (AUC = 0.827 versus 0.689, p = 0.000) and SI (AUC = 0.827 versus 0.688, p = 0.000). When using both DMS > 14.7 and AET > 4.8% or either of the two for the diagnosis of GERC, the diagnosis rate was not improved over using DMS > 14.7 alone. The diagnostic value of AET and DMS for acid GERC were both high and equivalent (AUC = 0.925 versus 0.922, p = 0.95). The optimal cutoff value of AET for diagnosing acid GERC was AET > 6.2%. CONCLUSION: AET and DMS are both equal in discriminating GERC. A GERC diagnosis should be considered when AET > 4.8%, whereas an acid GERC diagnosis should be considered when AET > 6.2%.