Unraveling the Complex Link Between Chronic Cough and GERD: Insights from Recent Studies

Introduction:

Chronic cough is a pervasive issue affecting a significant percentage of the population. Recently, Dr. Sabine Roman, an Associate Professor of Gastroenterology and Physiology at Lyon University Hospital in France, shed light on the intriguing connection between chronic cough and Gastroesophageal Reflux Disease (GERD) at the United European Gastroenterology Week. Let's delve into the key messages and findings she presented, challenging some common assumptions about this association.

The Overestimated Role of GERD:

While GERD is often considered a potential cause of chronic cough, Dr. Roman emphasized that this link might be overestimated. A Spanish study in 2023 revealed that GERD was suspected in 46% of cases, compared to 32% for asthma and 15% for postnasal drip. Surprisingly, only 43% of patients had consulted a gastroenterologist, and a mere 27% had undergone an endoscopy, raising questions about the accuracy of attributing chronic cough solely to GERD.

Causal Challenges and the Role of PPIs:

Establishing a clear cause-and-effect relationship between GERD and chronic cough proves challenging. Studies using automatic cough detection demonstrated that both GERD preceding a cough and the reverse scenario were observed, with both mechanisms coexisting in one-third of patients. Despite being commonly prescribed as a test treatment, proton pump inhibitors (PPIs) should not be considered definitive evidence of underlying GERD, particularly when characteristic symptoms like heartburn and acid reflux are absent.

Effectiveness of PPIs and Response Factors:

Dr. Roman highlighted that the efficacy of PPIs in treating chronic cough is not a guarantee of underlying GERD. Studies indicated that PPIs' improvement over a placebo ranged between 12% and 35% when GERD was proven. Response factors included typical symptoms, severe esophagitis, abnormal acid exposure, and low levels of nocturnal baseline impedance. Comprehensive testing for GERD is crucial before considering long-term PPI prescriptions for chronic cough patients.

Cough Reflex Threshold and Alternative Treatments:

Patients with GERD-related chronic cough often exhibit increased sensitivity to the cough reflex. Trials involving gabapentin and baclofen demonstrated roughly 50% improvement, with similar efficacy between the two. Lesogaberan, a GABA(B) receptor agonist, showed promise but has not been further developed. Anti-reflux surgery, while showing an 84% improvement in symptoms, requires careful patient screening due to factors influencing nonresponse or recurrence, such as extraesophageal symptoms like cough.

Conclusion:

In conclusion, the complex relationship between chronic cough and GERD challenges conventional assumptions. While PPIs may be prescribed as a first-line treatment for typical GERD symptoms, their effectiveness alone does not confirm GERD as the underlying cause of chronic cough. Comprehensive testing, including endoscopy and pH monitoring, is essential for accurate diagnosis and appropriate treatment decisions. As we navigate the evolving landscape of understanding GERD-related chronic cough, these insights contribute to a more nuanced and effective approach to patient care.