Temporal associations between coughing or wheezing and acid reflux in asthmatics

Background and aims-The pulmonary symptoms of patients with lung disease ma y be ascribed to gastro-oesophageal reflux although a causal relationship b etween acid reflux and coughing or wheezing has not been proved. Does cough cause reflux or does reflux cause cough? The aim of this study was to eval uate 24 hour oesophageal pH tracings of asthmatics with gastro-oesophageal reflux to determine the temporal association between acid reflux and coughi ng or wheezing. Methods-The oesophageal tracings of 128 asthmatics from the outpatient clin ics who underwent oesophagogastroduodenoscopy, oesophageal manometry, and 2 4 hour oesophageal pH monitoring were analysed. Three possible temporal rel ationships between the occurrence of acid reflux and the occurrence of coug hs or wheezes were evaluated: (1) pulmonary symptoms preceding reflux; (2) reflux preceding pulmonary symptoms; and (3) unrelated occurrence of both e vents. Results-Of 128 asthmatics, 53 recorded five or more coughs and 19 recorded three or more wheezes during the 24 hour recording period. Mean acid contac t time was similar in asthmatics with and without pulmonary symptoms (12.2 (1.2)% upsilon 10.4 (0.6)%). Of all coughs and wheezes, 46% and 48%, respec tively, were associated with acid reflux. For the individual asthmatic, the likelihood of reflux induced coughing increased as the number of coughs in creased. Conclusions-Half of all coughs and wheezes in asthmatics are associated wit h acid reflux into the oesophagus. While an occasional coughing episode can lead to reflux, it is rather the reflux episode in the vast majority of in stances that leads to cough.