Table 2 Characteristics of included studies

Brusasco

2003[17]

1207 patients >40 years, >10 pack years, FEV₁ ≤ 65% and FVC ≤ 70%

Tiotropium 18 μg

Salmeterol 50 μg

Placebo

6 months

Permitted: not stated

Not permitted: not stated

Casaburi

2002[21]

921 patients ≥ 40 years, ≥ 10 pack years, FEV₁ ≤ 65%, FVC ≤ 70%

Tiotropium 18 μg

Placebo

1 year

Permitted: Albuterol as needed, stable doses of theophylline, inhaled glucocorticosteroids and the equivalent of 10 mg oral prednisone/day, Not permitted: anticholinergics and long-acting β₂-agonists

Chan

2007[11]

913 patients ≥ 40 years, >10 pack years, FEV₁ ≤ 60% and FEV₁/FVC ≤ 0.70, ≥ 1 exacerbation in the past 2 years but not within 6 weeks before study

Tiotropium 18 μg

Placebo

1 year

Permitted: oral steroids at stable dose ≤ 10 mg prednisone/day, stable doses of inhaled steroids, theophylline, mucolytic, long-acting β₂-agonists; salbutamol for acute relief

Not permitted: inhaled anticholinergics or oral β₂-agonists

Dusser

2006[22]

1010 patients ≥ 40 years, 10 pack years, pre-bronchodilator FEV₁ 30-65% and FEV1/SVC ≤ 70%, ≥ 1 exacerbation in the last year but not within 6 weeks prior to the study

Tiotropium 18 μg

Placebo

48 weeks

Permitted: short-acting betagonists, concomitant use of inhaled or oral steroids (< 10 mg prednisone equivalent) at stable dosages, treatment of COPD exacerbations as deemed necessary

Not permitted: Longacting β₂-agonists, inhaled anticholinergics other than the study drug and theophylline

Niewoehner 2005[18]

1829 patients ≥ 40 years, ≥ 10 pack-years, FEV1 ≤ 60%

FVC ≤ 70%

Tiotropium 18 μg

Placebo

6 months

Permitted: Usual care authorized (including inhaled corticosteroids and long-acting β-agonists), antibiotics and systemic steroids for exacerbations.

Not permitted: other anticholinergic bronchodilators

Powrie

2007[10]

142 patients ≥ 10 pack years, FEV1 < 80% and FEV1/FVC < 70%

Tiotropium 18 μg

Placebo

1 year

Permited: usual medication

Not permitted: Anticholinergics other than the study drug

Tashkin

2008[13]

5992 patients ≥ 40 years, ≥ 10 pack years, FEV₁ ≤ 70% and FEV₁/FVC < 0.7, and perform satisfactory spirometry

Tiotropium 18 μg

Placebo

4 years

Permitted: usual medication

Not permitted: anticholinergics other than study drug unless for the treatment of exacerbations

Tonnel

2008[14]

554 patients ≥ 40 years, > 10 pack years, FEV₁ ≤ 70% and FEV₁/SVC < 0.7

Tiotropium 18 μg

Placebo

9 months

Permitted: salbutamol, stable dosage of theophylline, mucolytics, ICS and oral steroids (< 10 mg of prednisone)

Not permitted: β-blockers, antileukotrienes, oral or inhaled long-acting β₂-agonists, short-acting anticholinergics, or any other investigational drug

Vincken

2002[19]

535 patients ≥ 40 years, ≥ 10 pack-years, FEV1 ≤ 65% and FVC ≤ 70%

Tiotropium 18 μg

Ipratropium 40 mg

52 weeks

Permitted: salbutamol as needed; theophyllines, inhaled steroids and oral steroids (at a dose of ≤ 10 mg/day prednisolone or equivalent) if stable dosage.

Not permitted: other β₂-agonists (long or short acting) and inhaled anticholinergic medications (other than study drugs)