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.