Table 2—

Patient characteristics at entry to each study phase

CharacteristicStart of study#End of washout periodp-value
Total LCQ score+16.3 (14.1–17.9)15.9 (13.8–19.4)0.5
24-hr sputum volume mL5 (1.25–15)5 (1–13.1)0.3
FEV1 L1.68 (1.25–2.31)1.72 (1.19–2.10)0.8
FEV1 % pred75.7 (48.3–98.1)68.4 (53–107.1)
FVC L2.64 (1.9–3.65)2.82 (1.75–3.5)0.6
FVC % pred79.5 (68.2–95.4)81.6 (66.1–95.4)
FEV1/FVC0.63 (0.57–0.77)0.62 (0.56–0.82)0.7
FEV1/FVC % pred87.1 (77.6–104.4)97.0 (76.1–120)
FEF25–75% L·s−10.95 (0.64–1.54)1.09 (0.54–1.84)0.96
FEF25–75% % pred47.5 (21.9–64.8)44.8 (24.8–96.4)
MIP cmH2O43.5 (33.2–72.5)48 (32.5–61.5)0.2
MIP % pred58.5 (37.2–77.2)51.7 (31.1–63)
MEP cmH2O68.5 (58.5–95.2)67 (51–109)0.3
MEP % pred60.9 (41.9–83.4)51.3 (38.3–55.7)
Exercise capacity m220 (120–405)210 (137.5–357.5)1.0
Sputum bacterial load cfu·mL−13.8×106 (3.9×105–3.8×107)1.1×106 (1×103–1.1×108)0.6
Total SGRQ score§41.1 (24.6–44.8)40.4 (18.0–52.5)0.6
  • Data are presented as median (interquartile range), unless otherwise stated. LCQ: Leicester Cough Questionnaire; FEV1: forced expiratory volume in 1 s; % pred: % predicted; FVC: forced vital capacity; FEF25–75%: forced expiratory flow at 25–75% of FVC; MIP: maximum inspiratory pressure; MEP: maximum expiratory pressure; SGRQ: St George’s Respiratory Questionnaire. #: see point A on figure 1; : see point C on figure 1; +: the total severity score ranges from 3–21, a lower score indicates a more severe cough; §: the total score ranges from 0–100, a higher score indicates a poorer health-related quality of life.