TABLE 1

Characteristics of patients at enrolment and after withdrawal of tiotropium#

PlaceboTiotropiump-value
Subjects n126136
At enrolment (Tie-COPD)
 Age years62.4±8.362.4±7.40.98
 Male104 (82.5)120 (88.2)0.19
 BMI kg·m−221.8±3.222.2±3.40.35
 Smoking status0.62
  Never-smokers28 (22.2)27 (19.9)
  Current smokers60 (47.6)73 (53.7)
  Ex-smokers38 (30.2)36 (26.5)
 Smoking index pack-years48.1±26.744.7±21.90.52
 Duration of COPD days179±436125±2750.97
 Respiratory disease2 (1.6)4 (2.9)0.69
 Previous respiratory medications13 (10.3)16 (11.8)0.71
 Baseline before bronchodilator spirometry
  FEV1 L1.88±0.581.97±0.550.22
  FEV1 % pred77.2±19.577.6±18.30.89
  FVC L3.17±0.773.27±0.760.29
  FEV1/FVC ratio59.0±8.460.0±7.90.32
 Baseline after bronchodilator spirometry
  FEV1 L2.00±0.552.11±0.520.11
  FEV1 % pred82.2±17.983.0±16.60.68
  FVC L3.26±0.763.38±0.720.18
  FEV1/FVC ratio61.2±7.662.2±6.90.25
 Reversibility+22 (17.5)29 (21.3)0.43
 GOLD stage§0.60
  I72 (57.1)82 (60.3)
  II54 (42.9)54 (39.7)
 CAT scoreƒ
  Mean score4.0±3.34.5±4.20.53
  Distribution0.22
   <10119 (94.4)123 (90.4)
   ≥107 (5.6)13 (9.6)
 mMRC score##
  Mean score0.60±0.660.50±0.620.19
  Distribution0.39
   <2114 (90.5)127 (93.4)
   ≥212 (9.5)9 (6.6)
 CCQ score¶¶0.65±0.530.66±0.560.99
At follow-up (post-Tie-COPD)
 Respiratory medications0.35
  Use of respiratory medications41 (32.5)37 (27.2)
  No respiratory medications85 (67.5)99 (72.8)
 Bronchodilators0.54
  Use of bronchodilators27 (21.4)25 (18.4)
  No bronchodilators99 (78.6)111 (81.6)
 Smoking status0.73
  Never-smokers28 (22.2)25 (18.4)
  Current smokers59 (46.8)68 (50.0)
  Quit smoking39 (31.0)43 (31.6)

Data are presented as mean±sd or n (%), unless otherwise stated. Percentages may not sum to 100 because of rounding. Tie COPD: Tiotropium in Early COPD (chronic obstructive pulmonary disease); BMI: body mass index; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; GOLD: Global Initiative for Chronic Obstructive Lung Disease; CAT: COPD Assessment Test; mMRC: modified Medical Research Council; CCQ: Clinical COPD Questionnaire. #: there were no significant between-group differences for characteristics at enrolment. The analysis set included patients who underwent both Tie-COPD and post-Tie-COPD follow-up and had at least one available spirometric data measurement after bronchodilator use at Tie-COPD and at least one measurement at post-Tie-COPD follow-up; : p-values for continuous variables were calculated using t-test or the Wilcoxon rank-sum test, and p-values for categorical variables were calculated using the Chi-squared test; +: defined as an FEV1 value obtained after bronchodilator use that increased by ≥200 mL and by ≥12% from the measurement obtained before bronchodilator use; §: the GOLD staging system is used to assess the severity of lung disease. Stages range from 1 to 4, with higher stages indicating more severe disease. Stage 1 (mild disease) is defined as FEV1 ≥80% of the predicted value, and stage 2 (moderate disease) as FEV1 50–79% pred; ƒ: scores on the CAT range from 0 to 40, with higher scores indicating more severe disease; ##: the mMRC dyspnoea scale ranges from 0 to 4, with higher scores indicating more severe breathlessness; ¶¶: CCQ scores range from 0 to 6, with higher scores indicating worse clinical control.