Sun 2007.

Methods	Design: a randomised, double‐blind, parallel‐group, placebo‐controlled study with three months treatment duration, conducted in China
Participants	Population: 60 patients with COPD were randomised to tiotropium (30) and placebo (30) Baseline Characteristics: mean age 62 years, 63% to ‐77% male, mean FEV1 1.3 L, mean FEV1 predicted 47% Inclusion Criteria: a diagnosis of stable COPD, and an age of 18 to 70 years Exclusion Criteria: severe bronchial asthma, severe COPD, bronchiectasia, congestive heart‐ failure, pulmonary tuberculosis, systematic infection, particularly respiratory tract infection, in past two weeks before enrolment, severe heart, liver, kidney, blood system, nerve system, mental diseases and glaucoma, oversensitive to the experiment drugs, attended other trials in past one month, systematic chronic diseases such as hypertension, diabetes, hyperthyroid, etc.
Interventions	1. 18 mcg of tiotropium once daily 2. A matching placebo once daily Inhaler device: dry powder inhaler Co‐medication: salbutamol as needed
Outcomes	Primary: symptom improvement (%) = (scores before – scores after)/scores before x 100%; controlled: > 75%; marked improvement: 50% to 75%; improvement: 25% to 50%; no improvement: < 25% Secondary: COPD worsening: grade I: self treatment; Grade II: patients need to be treated by clinic; Grade III: hospitalisation is needed. Clinical symptoms including: cough, sputum, whoop, breathing difficulty, and lung rales; lung function including: 1 h predose FEV1 and FEV1 % predicted, FVC and FEV1/FVC; safety index including: blood, urine, liver and kidney function, chest X‐ray and ECG
Notes	Funding: not specified Definitions: exacerbations  level 1: could be treated by patients themselves; level 2: needed to be treated by Dept. of outpatients or Dept. of Emergency; level 3: needed hospitalisation.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	SAS software was used by stratification randomisation
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind study. The placebo had the same appearance as the intervention drug
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not described
Incomplete outcome data (attrition bias) All outcomes	Low risk	The withdrawal rates were relatively low but uneven (tiotropium 0%, placebo 10%)
Selective reporting (reporting bias)	Low risk	Results for all specified outcomes were reported