Clinical characteristics and use of healthcare resources by diagnosis of chronic cough

VariablesNo chronic coughChronic coughp-value
Subjects n49 0061985
Lung function#
 FEV1/FVC %82.0±0.475.2±1.2<0.0001
 FEV1 % pred99.8±0.994.5±2.50.0155
 FEV1/FVC <70%4420 (8.1)488 (22.8)0.0010
 MMEF % pred76.0±1.062.6±2.8<0.0001
 FEF 50% pred88.4±1.074.4±3.4<0.0001
 FEF 75% pred77.2±1.362.7±2.6<0.0001
 SAD15 991 (28.3)988 (48.0)0.0017
 Positive bronchodilator reversibility+3059 (6.1)222 (13.0)0.0315
Short form (SF)-12 scores
 PCS scores52.6±0.248.7±0.6<0.0001
 MCS scores54.1±0.353.1±0.60.0656
 Hypertension3846 (6.4)309 (13.1)0.0116
 Coronary heart disease698 (1.9)87 (3.2)0.3501
 Diabetes1203 (2.6)96 (3.9)0.2589
Acute exacerbation of respiratory symptoms in the last 12months
 Emergency174 (0.5)89 (3.5)0.0042
 Hospital admission167 (0.4)119 (5.5)0.0002

Values are weighted and shown as n (%) or mean±se. All the calculations of p-value are weighted, taking into account the multistage cluster sampling design and based on χ2 test for categorical variables or t-test for continuous variables. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; MMEF: maximal mid-expiratory flow; FEF50%: forced expiratory flow at 50% of the FVC; FEF 75%: forced expiratory flow at 75% of the FVC; SAD: small airway dysfunction; PCS: physical component summary; MCS: mental component summary. #: the parameters were measured at 20 min after inhalation of 400 µg of salbutamol; : SAD was diagnosed on the basis of at least two of the following three indicators of lung function being <65% of predicted – maximal mid-expiratory flow, forced expiratory flow (FEF) 50% and FEF 75% after bronchodilator inhalation. +: a positive bronchodilator reversibility test was defined as an increase in post-bronchodilator forced expiratory volume in 1 s of >12% and >200 mL from baseline, 20 min after inhalation of 400 µg of salbutamol.