Temporal correlation between chronic cough and gastroesophageal reflux disease

Reflux disease (GERD) and chronic cough often coexist, but a temporal correlation using the symptom association probability has not been reported. Our aim was to determine if a temporal correlation exists between cough and GERD. Sixty-one patients with chronic cough had esophageal pH monitoring with sensors 5 and 20 cm above the LES. The symptom (SI) and symptom sensitivity (SSI) indices and the symptom association probability (SAP) were used to test cough–reflux association. Pathological reflux was defined as the percentage of time pH <4 exceeded 4.2%. A significant temporal association between cough and distal reflux was made in 35% of patients by SAP compared with only 14.8% by SI and SSI alone (P < 0.002). Patients with pathologic reflux had a greater likelihood of a temporal symptom correlation (57.1%) when not on acid-blocking medications. In conclusion, a temporal association between cough and distal reflux exists in one third of patients, especially those with pathological reflux. The SAP is a more sensitive measure of temporal association than SI or SSI.