Table 1

 Characteristics and outcomes in healthy controls and patients with chronic cough

Chronic coughp values (ANOVA, Kruskal-Wallis test or χ2 test)
Healthy controls (n = 16)Asthma (n = 13)PND/rhinitis (n = 7)GOR (n = 5)Bronchiectasis (n = 5)Unidentified cause (n = 20)
Data are expressed as mean (SD) or median (range).
*p = 0.03, p = 0.01, **p = 0.005, ††p = 0.003 v control.
‡p = 0.03, §p = 0.01, ||p = 0.04 v patients with asthma.
PND = postnasal drip; GOR = gastro-oesophageal reflux; ICS = inhaled corticosteroids; NCS = nasal corticosteroids; LABA = long acting β agonists; PPI = proton pump inhibitors; FEV1 = forced expiratory volume in 1 second; C2, C5 = lowest concentration of capsaicin that induced ⩾2 or ⩾5 coughs, respectively; EBC = exhaled breath condensate.
Age (years)43 (8)44 (17)55 (7)*59 (5)†,‡62 (18)†,‡,§53 (12)†,||0.005
M/F4/126/70/71/41/43/170.23
Duration of cough (years)5.4 (5.5)11.4 (8.3)9.8 (5.5)10.7 (5.1)13.0 (7.8)0.08
Patients on medication3 (2 ICS, 1 ICS + LABA)3 (2 NCS, 1 nasal anticholinergic)1 (PPI)06 (2 NCS, 2 oral antihistamine, 1 NCS + PPI, 1 ICS + PPI)0.54
FEV1 (% predicted)100 (12)91 (16)88 (20)106 (18)98 (24)101 (20)0.27
C2 (μM)7.8 (0.98–500)3.9 (0.98–250)0.98 (0.98–15.6)0.98 (0.98–1.95)3.9 (0.98–125)1.47 (0.98–31.3)0.13
C5 (μM)125 (1.95–>500)31.3 (0.98–250)3.9 (0.98–15.6)**1.95 (0.98–15.6)††3.9 (0.98–500)2.93 (0.98–>500)††0.009