Acid gastroesophageal reflux (GERD) is one of the most important causes of chronic cough.
The response to acid suppression in these patients is not as good as in patients with heartburn but improvement with antireflux surgery has been reported, suggesting the involvement of a non-acidic gastric component in the refluxate.
Less acidic reflux may produce symptoms such as regurgitation or chest pain.
Dr Sifrim and colleagues from Belgium investigated whether chronic cough might be associated with weakly acidic reflux.
The investigators studied 28 patients with chronic cough using 24-hour ambulatory pressure-pH-impedance monitoring.
Manometry was used for precise recognition of cough and impedance-pHmetry to detect acid (pH less than 4), weakly acidic (pH 7 to 4), and weakly alkaline (impedance drops, pH 7) reflux.
The researchers performed a symptom association probability analysis for each type of reflux.
|Patients with chronic cough clearly associated with weakly acidic GERD|
The investigators completed analysis in 22 patients with 24 cough events (5–92 per patient).
The majority of cough events (69%) were considered "independent" of reflux whereas 31% occurred within 2 minutes of a reflux episode.
The research team noted that half of these (49%) were "reflux cough" sequences, involving acid (65%), weakly acidic (29%), and weakly alkaline (6%) reflux.
In addition, the team found that 45% patients had a positive symptom association probability between reflux and cough: 5 with acid, 2 with acid and weakly acidic, and 3 only with weakly acidic reflux.
Dr Sifrim concluded that, “Ambulatory pressure-pH-impedance monitoring with symptom association probability analysis allowed precise determination of the temporal association between cough and GERD (acid, weakly acidic, and weakly alkaline).”
“Identification of a subgroup of patients with chronic cough clearly associated with weakly acidic GERD.”