The researchers evaluated the 24-hour esophageal pH tracings of asthmatics with gastroesophageal reflux. This was to determine the temporal association between acid reflux and coughing or wheezing.
The findings of the study were published in the December issue of Gut.
The esophageal tracings of 128 asthmatics from the outpatient clinics were analyzed. Each underwent esophagogastroduodenoscopy, esophageal manometry, and 24-hour esophageal pH monitoring.
Three possible temporal relationships between the occurrence of acid reflux and the occurrence of coughs or wheezes were evaluated: (1) pulmonary symptoms preceding reflux; (2) reflux preceding pulmonary symptoms; and (3) unrelated occurrence of both events.
Of 128 asthmatics, 53 recorded 5 or more coughs, and 19 recorded 3 or more wheezes during the 24 hour recording period.
| Likelihood of reflux-induced coughing increased as number of coughs increased.
Mean acid contact time was similar in asthmatics with and without pulmonary symptoms (1.2% vs 0.6%).
Of all coughs and wheezes, 46% and 48%, respectively, were associated with acid reflux.
For the individual asthmatic, the likelihood of reflux-induced coughing was found to increase as the number of coughs increased.
B. Avidan, of the Department of Veterans Affairs Medical Center in Albuquerque, New Mexico, said on behalf of fellow authors, "Half of all coughs and wheezes in asthmatics are associated with acid reflux into the esophagus."
"While an occasional coughing episode can lead to reflux, it is rather the reflux episode in the vast majority of instances that leads to cough," it was concluded.