Acidity not sole determinant of reflux-induced chronic cough

Last Updated: 2017-03-31

By David Douglas

NEW YORK (Reuters Health) - Volume of reflux rather than acidity itself appears to play a more important role in reflux-induced chronic cough than has been previously appreciated, according to European researchers.

As Dr. Thomas V. K. Herregods of Academic Medical Centre in Amsterdam told Reuters Health by email, "Current medical treatment focuses on reducing acidity of the gastric content. Our study suggests that rather than reducing this acidity, decreasing the quantity of the refluxate could play a more important role in treating patients with reflux-induced chronic cough."

"Also," he added, "medication which targets the esophageal sensitivity might prove to have a good effect in these patients."

In a paper online March 16 in Gut, Dr. Herregods and colleagues note that it remains unclear why some reflux episodes in the same patient are associated with cough while others are not.

To investigate further, 49 patients with gastroesophageal reflux and reflux-associated chronic cough were followed using 24-hour pH-impedance-pressure monitoring.

They detected nearly 1,900 cough bursts manometrically. Of these, two-thirds were noted by the patients by pressing an event marker button on the pH data logger. Patients had a median of 31 cough bursts measured manometrically.

A reflux episode was considered associated with a cough burst if coughing began within two minutes of the episode. Episodes involving cough were then compared with those without cough.

Most reflux episodes (72.4%) were acidic. Compared with reflux episodes without cough, those with cough showed highly significant associations with higher proximal extent, higher volume clearance time and a higher acid burden in the preceding 15 minutes.

Further examination showed no significant differences between cough and absence of cough events in regard to nadir pH, the pH drop, the acid clearance time or the percentage of reflux episodes which were acidic.

“The presence of a larger volume of refluxate for a longer period of time seems to play a major role in inducing a cough burst, while the drop in pH, nadir pH or acid clearance time does not seem to be important,” the researchers write.

They add that medication that “decreases the quantity of the refluxate rather than reducing its acidity” might be useful. Drugs such as amitriptyline or citalopram, which target esophageal sensitivity, they conclude, could also be beneficial.

SOURCE: http://bit.ly/2nCEtit

Gut 2017.