• asthma
• gastrooesophageal reflux

We read with interest the report by Heaney et al¹ that the use of a systematic protocol for therapy resistant asthma resulted in control of asthma in 53% of patients who were previously poorly controlled. However, we suspect that a significant proportion of the remaining 47% of patients who were classified as having therapy resistant asthma actually had underlying gastro-oesophageal reflux disease which was either not adequately investigated (by 24 hour pH monitoring alone) or, once diagnosed, was not adequately treated (with standard dose proton pump inhibitor).

A large northern European study of 2661 subjects found that people with gastro-oesophageal reflux had a significantly higher rate of physician diagnosed current asthma and that those with reflux and asthma had more nocturnal cough, morning phlegm, sleep related symptoms, and more peak flow variability than those with asthma alone.² Pathological gastro-oesophageal reflux, which is often clinically silent, has been found on pH monitoring in 53–65% of asthmatics^3,4 and has been shown in various studies to cause increased capsaicin cough sensitivity,⁵ increased airway hyperresponsiveness,⁶ increased respiratory resistance,⁷ and increased respiratory symptoms.^3,4 Certainly, in the case of chronic cough, gastro-oesophageal reflux has been found to be one of the most frequent underlying causes.⁸

Heaney et al state that 17 patients with positive oesophageal pH monitoring were classified as having therapy resistant asthma because their respiratory symptoms did not improve with standard dose proton pump inhibitors. However, proton pump inhibitors have only a minor effect on the reflux of gastric contents; they alter the pH of the refluxate. This mode of action is effective in diseases such as oesophagitis where acid plays a vital role in pathogenesis. However, in airways disease non-acid reflux may be a major …