Ambulatory quantitative waking and sleeping cough assessment in patients with cystic fibrosis.

BACKGROUND: Although cough is a commonly reported symptom, objective quantitation of cough during normal activity has not been performed in patients with CF. METHODS: An ambulatory device was used to characterize cough over 24 hours. Pulmonary function and subject-reported coughing were also assessed. RESULTS: Patients included 19 clinically stable adults with CF (males:females=10:9; median age [range]=26 [19-57] years; median %-predicted FEV(1) [range]=65 [44-106]%). Median [range] cough rate was 27 [13-66] coughs/hour, with values while awake of 41 [20-102] and while asleep of 2 [0.1-7] (p<0.0001, Wilcoxon signed-rank test). Subjective reporting was consistent with objective data for wake-sleep differences, but correlated poorly with objective waking cough rate. CONCLUSIONS: Outpatient cough quantitation in patients with CF is feasible, indicates frequent coughing even during clinical stability, and may be useful in therapeutic trials in CF.