Sabine Roman, MD, PhD, associate professor of gastroenterology and physiology at Lyon University Hospital in France, took the floor at the United European Gastroenterology Week to discuss the link between a chronic cough and gastroesophageal reflux disease (GERD). During a session on extraesophageal symptoms, Dr. Roman relayed two key messages: In patients with a chronic cough, reflux absolutely must be documented, and proton pump inhibitors (PPIs) must only be prescribed when a diagnosis of GERD has been made.
Overestimated Cause
Chronic cough is a widespread problem with a prevalence of between 9% and 33%, according to clinical studies. The root causes of this cough are varied; they’re mainly related to the respiratory system (eg, asthma, chronic obstructive pulmonary disease, respiratory infections, or smoking) and the ear, nose, and throat field (eg, postnasal drip). What’s more, taking certain medicines, notably angiotensin-converting enzyme inhibitors, can also be at the root of this condition.
GERD is also a possible cause of a chronic cough but one that is likely overestimated. A 2023 Spanish study provides evidence of this; GERD was suspected to be linked to cough in 46% of patients (compared with 32% for asthma and 15% for postnasal drip).
The treatments most commonly prescribed include PPIs (79.6%) and respiratory medicines (87.8%). Note that antibiotics are administered empirically to 28.6% of patients. For Roman, “the blame for a chronic cough is too often assigned to GERD, especially considering that in this study, only 43% of patients had seen a gastroenterologist, 27% had an endoscopy, and 24% had undergone esophageal pH monitoring.”
Added to this observation is the difficulty of establishing a causal link between a cough and GERD when the latter is present, even when the patient has had a diagnosis of GERD. Of course, a link between the two does not necessarily imply a cause–effect relationship, especially given that studies have shown that a cough itself can induce GERD. Studies using automatic cough detection to count cough events have shown that GERD certainly preceded a cough in 48% of patients, but in 56% of cases, it was the cough that came before the GERD. What’s more, both mechanisms were present in one third of patients.
Prescribing PPIs Effectively
PPIs are commonly prescribed as a test treatment. However, their efficacy is in no way proof of the existence of underlying GERD. In reality, all placebo-controlled studies have shown that in cases where no prior diagnosis of GERD has been made, PPIs have no superior efficacy.
If reflux has been proven, then the improvement provided by PPIs, compared with placebo, is between 12% and 35%. Therefore, it is essential that the presence of GERD be demonstrated, particularly if the patient has no characteristic symptoms of GERD, such as heartburn and acid reflux.
Response factors to PPIs were evaluated in 178 Italian patients with a chronic cough who presented with suspected GERD. Of those, 45% responded to treatment. It has been shown that typical symptoms, severe esophagitis (grade C/D), abnormal acid exposure, and low levels of nocturnal baseline impedance were independent factors of response to treatment.
In conclusion, patients with a chronic cough must be comprehensively tested for GERD before a long-term prescription of PPIs can be considered.