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 24hours. 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 FEV1 [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.