The Link Between GERD and Cough

Summarized by Robert W. Griffith, MD
January 30, 2006

Introduction

It's recently become common to relate chronic cough to the existence of GERD (gastro-esophageal reflux disease). Studies have suggested that 20% to 40% of cases of chronic cough without an identifiable respiratory disease are due to GERD. These have been based on the presence of acid in the esophagus in many GERD patients; and have led to guidelines suggesting treatment for GERD in case this might be the cause.

Now a group of Australian physicians has analyzed published results of GERD treatment for chronic cough, and reported their results in the British Medical Journal. This is a summary of what they found.

What was done

Clinical studies were included in the analysis if they were randomized (i.e. patients randomly allocated to receive either active treatment or placebo), and involved any GERD treatment for a cough lasting more than 3 weeks without an underlying respiratory disorder. The types of treatment considered were: conservative measures (e.g raising the head of the bed, changing diet), H-2 receptor antagonist drugs (e.g. cimetidine or Tagamet®), proton-pump inhibitor drugs (e.g. omeprazole or Prilosec®), and surgery.

The main outcome assessed was failure to cure the cough at follow-up; other measures were the severity of the cough, side effects of treatment, and the frequency of complications (such as repeat surgery).

What was found

Eighty-four published studies were reviewed, and 11 of these were included in the final analysis (the others were unsuitable because of inadequate data). Three of these were in children, and 8 in adults.

The three studies in children were inconclusive - they were too small, or too few children completed the studies.

Five of the adult studies compared a proton pump inhibitor with placebo. Only three of these provided data on cure rates. Consequently, demonstration of the benefits of GERD medication on the cure of chronic cough was dependent on a total of 49 patients. At the end of the studies, 8 of 22 patients on protein pump inhibitors were cured of their cough, compared with 2 of 27 placebo patients. This difference was not statistically significant, but clearly pointed towards the possible benefit of this treatment. The authors calculated 5 patients would need to be treated this way in order to achieve one patient with a cure of their cough.

There was insufficient information to be able to analyze the possible benefits of the other GERD treatments (conservative, H-2 antagonists, and surgery). It was also not possible to demonstrate benefits of the proton pump inhibitors on the severity of the cough in those patients who were not cured, except in the case of two cross-over studies ¹, which are regarded as being less reliable in design. There was no evidence that GERD treatment was associated with side effects.

What these analyses show

First, the total information from this work was disappointing - only one type of GERD treatment could be analyzed, and the number of qualified patients for this was rather small. Second, the benefit of proton pump inhibitors was established, more or less, but it was not nearly as clear cut as expected.

The authors conclude that "proton pump inhibitors for cough associated with GERD probably have some effect in adults, though this effect is less universal than reported . . ." It seems that recommendations on treating chronic cough with GERD medications need to be somewhat moderated. If GERD symptoms as well as chronic cough are present in the same patient, it is worth treating ther GERD in the hope that the cough will clear up. But the doctor should make sure that there isn't an underlying respiratory cause for the cough!

Source

• Systematic review and meta-analysis of randomized controlled trials of gastro-oesophageal reflux intervention for chronic cough associated with gastro-oesophageal reflux. AB. Chang, TJ. Stamler, TO. Kiljander,  et al., BMJ, 2006, vol. 332, pp. 11--17

Footnotes
1. In cross-over studies, the patients receive one treatment (drug or placebo) for a period of time, followed by the alternative treatment for the same period. For a number of reasons, they are considered less reliable than parallel group studies (such as one group given drug and another group given placebo, at the same time).

Related Links
GERD or GORD, It's Still a Pain
Treating GERD Symptoms May Facilitate Pneumonia
NIH: Heartburn, Hiatal Hernia, and GERD

Please take a moment to give us your comments. For questions about Health matters you may check our "Questions & Answers" Portal and Service.