24-h esophageal pH testing in asthmatics: respiratory symptom correlation with esophageal acid events

Gastroesophageal reflux (GER) may be a trigger for asthma and may be clinically silent. Twenty-four-hour esophageal pH testing accurately diagnoses GER in asthmatics. There are no reports correlating respiratory symptoms with esophageal acid events. This study examines the prevalence and severity of GER in asthmatics with and without reflux symptoms and examines respiratory symptom correlation with esophageal acid.

All esophageal manometry and 24-h esophageal pH tests performed were reviewed in asthmatics who met entrance criteria from July 1, 1989, through November 1, 1994. GER was present if esophageal pH tests were abnormal. Results of esophageal tests were compared for asthmatics with reflux symptoms and GER and asthmatics without reflux symptoms and GER. Respiratory symptoms correlated with esophageal acid events if the esophageal pH was < 4 simultaneously with the respiratory event or within 5 min before its onset.

Of 199 asthmatics who qualified for analysis, 164 (82%) had reflux symptoms. The results of 24-h esophageal pH tests were abnormal in 118 of 164 asthmatics with reflux symptoms (72%), compared with 10 of 35 asthmatics without reflux symptoms (29%). Among asthmatics with GER, 119 of 151 respiratory symptoms (78.8%) were associated with esophageal acid. Seventy-six of 84 reported coughs (90.5%) were associated with esophageal acid. Theophylline did not alter esophageal parameters.

There is a strong correlation between esophageal acid events and respiratory symptoms in asthmatics with GER. Respiratory symptom correlation with esophageal acid events further supports that GER may be a trigger for asthma.